LIFESPAN DEVELOPMENT
Third Edition
To my parents, Philip and Irene Kuther
Sara Miller McCune founded SAGE Publishing in 1965 to support the
dissemination of usable knowledge and educate a global community.
SAGE publishes more than 1,000 journals and over 600 new books
each year, spanning a wide range of subject areas. Our growing
selection of library products includes archives, data, case studies, and
video. SAGE remains majority owned by our founder and after her
lifetime will become owned by a charitable trust that secures the
company’s continued independence.
Los Angeles | London | New Delhi | Singapore | Washington DC |
Melbourne
LIFESPAN DEVELOPMENT
Lives in Context
Third Edition
Tara L. Kuther
Los Angeles
London
New Delhi
Singapore
Washington DC
Melbourne
Copyright © 2023 by SAGE Publications, Inc.
All rights reserved. Except as permitted by U.S. copyright law, no part
of this work may be reproduced or distributed in any form or by any
means, or stored in a database or retrieval system, without
permission in writing from the publisher.
All third party trademarks referenced or depicted herein are included
solely for the purpose of illustration and are the property of their
respective owners. Reference to these trademarks in no way indicates
any relationship with, or endorsement by, the trademark owner.
FOR INFORMATION:
SAGE Publications, Inc.
2455 Teller Road
Thousand Oaks, California 91320
E-mail: order@sagepub.com
SAGE Publications Ltd.
1 Oliver’s Yard
55 City Road
London, EC1Y 1SP
United Kingdom
SAGE Publications India Pvt. Ltd.
B 1/I 1 Mohan Cooperative Industrial Area
Mathura Road, New Delhi 110 044
India
SAGE Publications Asia-Pacific Pte. Ltd.
18 Cross Street #10-10/11/12
China Square Central
Singapore 048423
ISBN: 978-1-0718-5194-4
Library of Congress Control Number: 2022902708
Printed in the United States of America
This book is printed on acid-free paper.
22 23 24 25 26 10 9 8 7 6 5 4 3 2 1
Acquisitions Editor: Lara Parra
Content Development Editor: Emma Newsom
Production Editor: Veronica Stapleton Hooper
Copy Editor: Terri Lee Paulsen
Typesetter: diacriTech
Cover Designer: Gail Buschman
Marketing Manager: Victoria Velasquez
BRIEF CONTENTS
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
Preface
Acknowledgments
About the Author
Part I Foundations of Lifespan Human Development
Chapter 1 Understanding Human Development: Approaches and
Theories
Chapter 2 Biological and Environmental Foundations of
Development
Chapter 3 The Prenatal Period, Birth, and the Newborn
Part II Infancy and Toddlerhood
Chapter 4 Physical Development in Infancy and Toddlerhood
Chapter 5 Cognitive Development in Infancy and Toddlerhood
Chapter 6 Socioemotional Development in Infancy and
Toddlerhood
Part III Early Childhood
Chapter 7 Physical and Cognitive Development in Early
Childhood
Chapter 8 Socioemotional Development in Early Childhood
Part IV Middle Childhood
Chapter 9 Physical and Cognitive Development in Middle
Childhood
Chapter 10 Socioemotional Development in Middle Childhood
Part V Adolescence
Chapter 11 Physical and Cognitive Development in Adolescence
Chapter 12 Socioemotional Development in Adolescence
Part VI Emerging and Early Adulthood
Chapter 13 Physical and Cognitive Development in Emerging
and Early Adulthood
Chapter 14 Socioemotional Development in Emerging and Early
Adulthood
Part VII Middle Adulthood
Chapter 15 Physical and Cognitive Development in Middle
Adulthood
Chapter 16 Socioemotional Development in Middle Adulthood
Part VIII Late Adulthood
Chapter 17 Physical and Cognitive Development in Late
Adulthood
Chapter 18 Socioemotional Development in Late Adulthood
Part IX Endings
31.
32.
33.
34.
35.
Chapter 19 Death and Dying
Glossary
References
Name Index
Subject Index
DETAILED CONTENTS
Preface
Acknowledgments
About the Author
Part I Foundations of Lifespan Human Development
Chapter 1 Understanding Human Development: Approaches and
Theories
What Is Lifespan Human Development?
Development Is Multidimensional
Development Is Multidirectional
Development Is Plastic
Development Is Influenced by Multiple Contexts
Sociohistorical Context
Cultural Context
Developmental Science Is Multidisciplinary
Thinking in Context: Lifespan Development
Basic Issues in Lifespan Human Development
Development Is Characterized by Continuous and
Discontinuous Change
Individuals Are Active in Development
Nature and Nurture Influence Development
Thinking in Context: Lifespan Development
Thinking in Context: Biological Influences
Theoretical Perspectives on Human Development
Psychoanalytic Theories
Freud’s Psychosexual Theory
Erikson’s Psychosocial Theory
Behaviorist and Social Learning Theories
Classical Conditioning
Operant Conditioning
Social Learning Theory
Cognitive Theories
Piaget’s Cognitive–Developmental Theory
Information Processing Theory
Contextual Theories
Vygotsky’s Sociocultural Theory
Bronfenbrenner’s Bioecological Systems Theory
Dynamic Systems Theory
Ethology and Evolutionary Developmental Theory
Thinking in Context: Applied Developmental Science
Research in Human Development
The Scientific Method
Methods of Data Collection
Observational Measures
Self-Report Measures
Physiological Measures
Research Designs
Case Study
Correlational Research
Experimental Research
Developmental Research Designs
Cross-Sectional Research Design
Longitudinal Research Design
Sequential Research Designs
Thinking in Context: Applied Developmental Science
Research Ethics
Principles of Research Ethics
Ethical Issues in Studying Lifespan Human
Development
Informed Consent
Confidentiality
Thinking in Context: Applied Developmental Science
Thinking in Context: Intersectionality
Applied Developmental Science and Intersectionality
Applied Developmental Science
Intersectionality and Development
Thinking in Context: Intersectionality
Apply Your Knowledge
Chapter Summary
Key Terms
Chapter 2 Biological and Environmental Foundations of
Development
Genetic Foundations of Development
Genetics
Cell Reproduction
Sex Determination
Genes Shared by Twins
Patterns of Genetic Inheritance
Dominant–Recessive Inheritance
Incomplete Dominance
Polygenic Inheritance
Genomic Imprinting
Thinking in Context: Biological Influences
Chromosomal and Genetic Problems
Genetic Disorders
Dominant–Recessive Disorders
X-Linked Disorders
Chromosomal Abnormalities
Mutation
Thinking in Context: Biological Influences
Thinking in Context: Lifespan Development
Reproductive Choices: Genetic Counseling Assisted
Reproductive Technology
Genetic Counseling
Assisted Reproductive Technology
Artificial Insemination
In Vitro Fertilization
Surrogacy
Assisted Reproductive Technology and Sex Selection
Thinking in Context: Applied Developmental Science
Thinking in Context: Intersectionality
Reproductive Choices: Adoption
Adoption and Child Outcomes
Transracial Adoption
International Adoption
Thinking in Context: Intersectionality
Thinking in Context: Lifespan Development
Prenatal Diagnosis
Methods of Prenatal Diagnosis
Prenatal Treatment of Genetic Disorders
Thinking in Context: Applied Developmental Science
Heredity and Environment: Behavior Genetics
Methods of Behavior Genetics
Genetic Influences on Personal Characteristics
Thinking in Context: Applied Developmental Science
Gene–Environment Interactions
Range of Reaction
Canalization
Gene–Environment Correlations
Gene–Environment (G x E) Interactions
Epigenetic Framework
Thinking in Context: Lifespan Development
Thinking in Context: Biological Influences
Apply Your Knowledge
Chapter Summary
Key Terms
Chapter 3 The Prenatal Period, Birth, and the Newborn
Prenatal Development
Conception
Germinal Period (0 to 2 Weeks)
Embryonic Period (3 to 8 Weeks)
Fetal Period (9 Weeks to Birth)
Thinking in Context: Applied Developmental Science
Environmental Influences on Prenatal Development
Principles of Teratology
Critical Periods
Dose
Individual Differences
Complicated Effects
Types of Teratogens
Prescription and Nonprescription Drugs
Alcohol
Cigarette Smoking and E-Cigarette Use
Marijuana
Cocaine
Opioids
Maternal Illness
Environmental Hazards
Contextual Factors and Teratogens
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Thinking in Context: Applied Developmental Science
Maternal and Paternal Characteristics and Prenatal
Development
Maternal Characteristics
Nutrition
Emotional Well-Being
Maternal Age
Paternal Characteristics
Thinking in Context: Lifespan Development
Contextual and Cultural Influences on Prenatal Care
Barriers to Prenatal Care
Race, Ethnicity, and Prenatal Care
Thinking in Context: Intersectionality
Thinking in Context: Lifespan Development
Childbirth
Labor
Medication During Delivery
Cesarean Delivery
Natural Childbirth
Home Birth
Cultural Differences in Childbirth
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Low-Birthweight Infants: Preterm and Small-for-Date Babies
Contextual Risks for LBW
Characteristics of LBW Infants
Promoting Positive Outcomes of LBW Infants
Thinking in Context: Lifespan Development
The Newborn
Medical and Behavioral Assessment of Newborns
The Newborn’s Perceptual Capacities
Newborn States of Arousal
Thinking in Context: Biological Influences
Thinking in Context: Applied Developmental Science
Apply Your Knowledge
Chapter Summary
Key Terms
Lifespan Development at Work Part 1: Foundations of
Lifespan Human Development
Careers in Genetics and Prenatal Development
Part II Infancy and Toddlerhood
Chapter 4 Physical Development in Infancy and Toddlerhood
Body Growth During Infancy and Toddlerhood
Growth Trends
Patterns of Growth
Nutrition and Growth
Breastfeeding
Complementary Food
Thinking in Context: Applied Developmental Science
Threats to Infant Health
Infant Mortality
Malnutrition
Growth Faltering
Failure to Vaccinate
Sudden Infant Death Syndrome
Thinking in Context: Intersectionality
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Brain Development During Infancy and Toddlerhood
The Neuron
Processes of Neural Development
The Cerebral Cortex
Experience and Brain Development
Sleep and Brain Development
Thinking in Context: Lifespan Development
Thinking in Context: Biological Influences
Early Learning Capacities
Habituation
Classical Conditioning
Operant Conditioning
Imitation
Thinking in Context: Applied Developmental Science
Sensation and Perception During Infancy and Toddlerhood
Methods for Studying Infant Perception
Vision
Face Perception
Object Exploration
Color Vision
Depth Perception
Hearing
Touch
Smell and Taste
Intermodal Perception
Infant–Context Interactions and Perceptual
Development
Thinking in Context: Applied Developmental Science
Thinking in Context: Lifespan Development
Thinking in Context: Biological Influences
Motor Development During Infancy and Toddlerhood
Gross Motor Development
Fine Motor Development
Biological and Contextual Determinants of Motor
Development
Biological Influences on Motor Development
Contextual Influences on Motor Development
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Apply Your Knowledge
Chapter Summary
Key Terms
Chapter 5 Cognitive Development in Infancy and Toddlerhood
Piaget’s Cognitive-Developmental Theory: Sensorimotor
Reasoning
Processes of Development
Sensorimotor Substages
Substage 1: Reflexes (Birth to 1 Month)
Substage 2: Primary Circular Reactions (1 to 4
Months)
Substage 3: Secondary Circular Reactions (4 to 8
Months)
Substage 4: Coordination of Secondary Circular
Reactions (8 to 12 Months)
Substage 5: Tertiary Circular Reactions (12 to 18
Months)
Substage 6: Mental Representation (18 to 24
Months)
Thinking in Context: Applied Developmental Science
Evaluating Sensorimotor Reasoning
Methods for Studying Object Permanence
Violation-of-Expectation Tasks
A-Not-B Tasks
Deferred Imitation Tasks
Core Knowledge Theory
Thinking in Context: Applied Developmental Science
Thinking in Context: Lifespan Development
Information Processing Theory
Information Processing System
Attention
Memory
Working Memory
Long-Term Memory
Infants’ Thinking
Culture and Cognitive Development
New Contexts for Learning: Screens and Digital
Media
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Individual Differences in Cognitive Abilities
Testing Infant Intelligence
Information Processing as Intelligence
Child Care and Cognitive Development
Poverty and Cognitive Development
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Language Development in Infancy and Toddlerhood
Early Preferences for Speech Sounds
Prelinguistic Communication
Putting Words Together
First Words
Learning Words: Semantic Growth
Two-Word Utterances
Infant Gesture and Sign Language
Language Development in Bilingual Infants
Language Development in Deaf Infants
Thinking in Context: Lifespan Development
Influences on Language Development: Interactionist
Perspective
Nativism
Evolution and Brain Development
Social Learning
Infant-Directed Speech
Cultural Differences in Infant-Directed Speech
Parental Responsiveness
Thinking in Context: Biological Influences
Thinking in Context: Applied Developmental Science
Apply Your Knowledge
Chapter Summary
Key Terms
Chapter 6 Socioemotional Development in Infancy and
Toddlerhood
Psychosocial Development in Infancy and Toddlerhood
Trust Versus Mistrust
Autonomy Versus Shame and Doubt
Thinking in Context: Applied Developmental Science
Thinking in Context: Lifespan Development
Emotional Development in Infancy and Toddlerhood
Infants’ Emotional Experience
Basic Emotions
Self-Conscious Emotions
Emotion Regulation
Social Interaction and Emotional Development
Sensitive Caregiving
Parent–Infant Interaction
Social Referencing
Exposure to Early Life Stress
Cultural Influences on Emotional Development
Caregiver Responsiveness
Emotional Socialization
Stranger Wariness
Thinking in Context: Lifespan Development
Temperament in Infancy and Toddlerhood
Styles of Temperament
Context and Goodness of Fit
Cultural Differences in Temperament
Thinking in Context: Lifespan Development
Attachment in Infancy and Toddlerhood
Bowlby’s Ethological Theory of Attachment
Infants’ Signals and Adults’ Responses
Phases of Attachment
Secure Base, Separation Anxiety, and Internal
Working Models
Ainsworth’s Strange Situation
Influences on Attachment
Maternal Depression and Attachment
Father–Infant Attachment
Stability of Attachment
Cultural Variations in Attachment Classifications
Thinking in Context: Biological Influences
Thinking in Context: Applied Developmental Science
Thinking in Context: Intersectionality
The Self in Infancy and Toddlerhood
Self-Awareness
Self-Recognition
Emerging Self-Concept
Self-Control
Thinking in Context: Lifespan Development
Apply Your Knowledge
Chapter Summary
Key Terms
Lifespan Development at Work Part 2: Infancy and
Toddlerhood
Part III Early Childhood
Chapter 7 Physical and Cognitive Development in Early
Childhood
Growth and Motor Development in Early Childhood
Body Growth
Motor Development
Gross Motor Skills
Fine Motor Skills
Brain Development
Thinking in Context: Lifespan Development
Thinking in Context: Biological Influences
Health and Threats to Health in Early Childhood
Nutrition and Eating Habits
Physical Activity
Sleep
Screen Use
Illness and Toxins
Unintentional Injuries
Thinking in Context: Applied Developmental Science
Thinking in Context: Intersectionality
Cognitive-Developmental and Sociocultural Reasoning in
Early Childhood
Piaget’s Cognitive-Developmental Perspective:
Preoperational Reasoning
Characteristics of Preoperational Reasoning
Evaluating Preoperational Reasoning
Vygotsky’s Sociocultural Perspective
Guided Participation and Scaffolding
Zone of Proximal Development
Private Speech
Evaluating Vygotsky’s Sociocultural Perspective
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Information Processing in Early Childhood
Attention
Working Memory and Executive Function
Memory
Memory Strategies
Autobiographical Memory
Memory Suggestibility
Theory of Mind
False Belief
Context, Culture, and Theory of Mind
Metacognition
Thinking in Context: Applied Developmental Science
Thinking in Context: Lifespan Development
Young Children’s Language Development
Vocabulary
Grammar
Bilingual Language Learning
Context and Language Development
Socioeconomic Status and Language Development
Race, Socioeconomic Status, and Language
Development
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Early Childhood Education
Child-Centered and Academically Centered Preschool
Programs
Early Childhood Education Interventions
Thinking in Context: Applied Developmental Science
Thinking in Context: Lifespan Development
Apply Your Knowledge
Chapter Summary
Key Terms
Chapter 8 Socioemotional Development in Early Childhood
Emerging Sense of Self
Psychosocial Development in Early Childhood
Self-Concept
Self-Esteem
Thinking in Context: Lifespan Development
Emotional Development in Early Childhood
Emotional Understanding
Emotion Regulation
Empathy
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Moral Development and Behavior in Early Childhood
Theories of Moral Reasoning and Behavior
Social Learning Theory
Cognitive-Developmental Theory
Children’s Conceptions of Moral, Social, and
Personal Issues
Prosocial Behavior
Influences on Prosocial Behavior
Aggressive Behavior
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Families in Early Childhood
Parenting Styles
Authoritarian Parenting Style
Permissive Parenting Style
Uninvolved Parenting Style
Authoritative Parenting Style
Discipline
Physical Punishment
Inductive Discipline
Culture, Context, and Parenting
Child Maltreatment
Effects of Child Maltreatment
Risk Factors for Child Maltreatment
Thinking in Context: Applied Developmental Science
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Gender Stereotypes, Gender Differences, and Gender Typing
Sex Differences
Gender Stereotypes and Gender Typing
Biological Influences on Gender Typing
Cognitive Influences on Gender Role Typing
Gender Identity and Gender Constancy
Gender Schema
Contextual Influences on Gender Role Typing
Parents
Peers
Media
Transgender Identity
Reducing Gender Stereotyping
Thinking in Context: Biological Influences
Thinking in Context: Applied Developmental Science
Play and Peer Relationships in Early Childhood
Play and Development
Cognitive and Emotional Development
Social Development and Early Friendships
Sociodramatic Play
Rough-and-Tumble Play
Imaginary Companions
Culture and Play
Thinking in Context: Applied Developmental Science
Apply Your Knowledge
Chapter Summary
Key Terms
Lifespan Development at Work Part 3: Early Childhood
Part IV Middle Childhood
Chapter 9 Physical and Cognitive Development in Middle
Childhood
Physical and Motor Development in Middle Childhood
Body Growth
Brain Development
Adrenarche
Motor Development
Thinking in Context: Lifespan Development
Thinking in Context: Biological Influences
Health in Middle Childhood
Physical Activity in Middle Childhood
Childhood Injuries and Mortality
Childhood Obesity
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Thinking in Context: Intersectionality
Developmental Disabilities in Middle Childhood
Attention-Deficit/Hyperactivity Disorder
Autism Spectrum Disorders
Specific Learning Disorder
Context and Disability: Race and Socioeconomic Status
Thinking in Context: Biological Influences
Thinking in Context: Applied Developmental Science
Thinking in Context: Intersectionality
Cognitive Development in Middle Childhood
Piaget’s Cognitive-Developmental Theory: Concrete
Operational Reasoning
Classification
Conservation
Culture and Concrete Operational Reasoning
Implications of Cognitive-Developmental Theory
for Education
Information Processing and Cognition
Working Memory and Executive Function
Metacognition and Metamemory
Memory Strategies
Context and Cognition
Implications of Information Processing for
Education
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Intelligence in Middle Childhood
Intelligence Tests
Individual and Group Differences in IQ
Contextual Influences on IQ
SES and IQ
Sociohistorical Context and IQ
IQ and the Majority Culture
Stereotypes and IQ
Alternative Views of Intelligence
Multiple Intelligences
Triarchic Theory of Intelligence
Thinking in Context: Intersectionality
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Language Development in Middle Childhood
Vocabulary
Grammar
Pragmatics
Bilingual Language Learning
Thinking in Context: Lifespan Development
Learning and Schooling in Middle Childhood
Approaches to Education
Reading and Mathematics Instruction
Access to Digital Technology and Learning
Educating Children With Special Needs
Thinking in Context: Lifespan Development
Apply Your Knowledge
Chapter Summary
Key Terms
Chapter 10 Socioemotional Development in Middle Childhood
Psychosocial Development in Middle Childhood
Self-Concept
Self-Esteem
Body Image
Achievement Motivation
Thinking in Context: Intersectionality
Thinking in Context: Lifespan Development
Thinking in Context: Biological Influences
Moral Development in Middle Childhood
Reasoning About Rules: Piaget’s Theory
Conceptions of Justice: Kohlberg’s Theory of Moral
Reasoning
Preconventional Reasoning
Distributive Justice: Reasoning About Sharing
Conceptions of Moral, Social, and Personal Issues
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Gender Differences and Gender Typing
Boys and Girls: Similarities and Differences
Gender Stereotypes and Gender Beliefs
Gender Constancy and Gender Typing
Gender Identity
Perceived Same-Gender Typicality and Perceived
Other-Gender Typicality
Gender Contentedness
Perceived Pressure to Conform to Gender Roles
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Peer Relationships in Middle Childhood
Friendship
Peer Acceptance, Popularity, and Rejection
Popularity
Peer Rejection
Bullying
Children Who Bully
Victims of Bullying
Contextual Approaches to Bullying Intervention
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Families in Middle Childhood
Parent–Child Relationships
Siblings
Only Children
Same-Sex Parented Families
Single-Parent Families
Cohabiting Families
Divorced and Divorcing Families
Blended Families
Thinking in Context: Lifespan Development
Risk and Resilience in Middle Childhood
Parental Incarceration
Parental Deployment
Exposure to Community Violence
Child Sexual Abuse
Resilience in Middle Childhood
Thinking in Context: Lifespan Development
Apply Your Knowledge
Chapter Summary
Key Terms
Lifespan Development at Work Part 4: Middle Childhood
Part V Adolescence
Chapter 11 Physical and Cognitive Development in Adolescence
Puberty
Changes in Body Shape and Size
Emergence of Secondary Sex Characteristics
Maturation of Primary Sex Characteristics
Menarche
Spermarche
Pubertal Timing and Adolescent Development
Early Maturation
Late Maturation
Context and the Effects of Pubertal Timing
Biological and Contextual Influences on Pubertal
Timing
Thinking in Context: Biological Influences
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Thinking in Context: Applied Developmental Science
Health in Adolescence
Nutrition
Physical Activity and Exercise
Sleep
Adolescent Mortality
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Brain Development in Adolescence
Changes in Brain Volume and Structure
Changes in Brain Structure and Function
Experience and the Adolescent Brain
Stress
Substance Use
Brain Development and Behavior
Socioemotional Perception
Reward Perception
Thinking in Context: Biological Influences
Thinking in Context: Applied Developmental Science
Cognitive Development in Adolescence
Piaget’s Cognitive-Developmental Theory: Formal
Operational Reasoning
Formal Operational Reasoning
Evaluating Formal Operational Reasoning
Information Processing
Attention
Working Memory and Executive Function
Processing Speed
Metacognition
Social Cognition
Perspective Taking
Adolescent Egocentrism
Decision-Making
Thinking in Context: Lifespan Development
School Context in Adolescence
Shifting Contexts
Stage–Environment Fit
Contextual Influences on Academic Achievement
Teachers
Parents
Peers
School Dropout
Adolescent Employment
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Apply Your Knowledge
Chapter Summary
Key Terms
Chapter 12 Socioemotional Development in Adolescence
Psychosocial Development: The Changing Self
Self-Concept
Self-Esteem
Identity
Identity Statuses
Influences on Identity Development
Outcomes Associated with Identity Development
Ethnic–Racial Identity
Gender Intensification and Transgender Identity
Spirituality and Religiosity
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Moral and Civic Development in Adolescence
Moral Reasoning
Changes in Moral Reasoning
Influences on Moral Reasoning
Gender and Moral Reasoning
Culture and Moral Reasoning
Moral Reasoning and Behavior
Civic Development
Civic Engagement
Critical Consciousness
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Adolescents and Their Parents
Parent–Adolescent Conflict
Parenting and Adjustment
Thinking in Context: Lifespan Development
Adolescents and Their Peers
Friendships
Cliques and Crowds
Peer Conformity
Peers, Social Media, and Cyberbullying
Dating
Developmental Shifts in Dating
Dating and Psychosocial Adjustment
Dating Violence
Thinking in Context: Applied Developmental Science
Thinking in Context: Lifespan Development
Adolescent Sexuality
Sexual Activity
Lesbian, Gay, and Bisexual Adolescents
Sexting
Contraceptive Use
Sexually Transmitted Infections
Adolescent Pregnancy
Sexuality Education
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Problems in Adolescence
Depression and Suicide
Eating Disorders
Anorexia Nervosa and Bulimia Nervosa
Binge Eating Disorder
Alcohol and Substance Use
Delinquency
Thinking in Context: Biological Influences
Thinking in Context: Lifespan Development
Apply Your Knowledge
Chapter Summary
Key Terms
Lifespan Development at Work Part 5: Adolescence
Part VI Emerging and Early Adulthood
Chapter 13 Physical and Cognitive Development in Emerging
and Early Adulthood
Physical Development in Emerging and Early Adulthood
Theories of Aging: What Causes Aging?
Physical Changes
Fertility and Reproductive Capacity
Thinking in Context: Biological Influences
Thinking in Context: Lifespan Development
Health and Fitness During Emerging and Early Adulthood
Overweight and Obesity
Physical Activity
Substance Abuse
Alcohol
Marijuana
Tobacco
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Cognitive Development in Emerging and Early Adulthood
fPostformal Reasoning
Pragmatic Thought and Cognitive-Affective Complexity
Evaluating Cognitive-Developmental Approaches to
Adult Development
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Education in Emerging and Early Adulthood
Developmental Impact of Attending College
First-Generation College Students
Nontraditional College Students
Students With Developmental Disabilities
Not Attending College
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Thinking in Context: Applied Developmental Science
Career Development in Emerging and Early Adulthood
Occupational Stages
Influences on Vocational Choice
Transition to Work
Intersectionality and the Workplace
Work–Life Balance
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Apply Your Knowledge
Chapter Summary
Key Terms
Chapter 14 Socioemotional Development in Emerging and Early
Adulthood
Emerging Adulthood
Characteristics of Emerging Adulthood
Demographic Instability
Subjective Sense of Feeling In-Between
Identity Exploration, Self-Focus, and Optimism
Contextual Nature of Emerging Adulthood
Emerging Adulthood and Culture
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Psychosocial Development
Identity Versus Role Confusion
Moral Identity
Religious Identity
Political Identity
Gender Identity and Sexual Identity
Ethnic–Racial Identity
Intimacy Versus Isolation
Attachment
The Social Clock
Thinking in Context: Lifespan Development
Sexual Activity
Sexual Activity
Casual Sex
Sexual Coercion and Assault
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Relationships and Psychosocial Development
Friendship
Romantic Relationships
Mate Selection
Technology and Mate Selection
Components of Love
Intimate Partner Violence
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Romantic Partnerships and Lifestyles
Singlehood
Cohabitation
Marriage
Same-Sex Marriage
Divorce
Thinking in Context: Lifespan Development
Parenthood
Becoming a Parent
Nonmarital Childbearing
Same-Sex Parents
Stepparents
Childlessness
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Thinking in Context: Biological Influences
Apply Your Knowledge
Chapter Summary
Key Terms
Lifespan Development at Work Part 6: Early Adulthood
Part VII Middle Adulthood
Chapter 15 Physical and Cognitive Development in Middle
Adulthood
Physical Development in Middle Adulthood
Sensory Aging
Vision
Hearing
Skin
Body Composition
Reproductive Aging
Reproductive Changes in Women
Reproductive Changes in Men
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Thinking in Context: Biological Influences
Health
Mortality
Common Illnesses
Cancer
Cardiovascular Disease
Diabetes
Stress and Health
Stress
Stress Reactivity
Hardiness and Stress
Thinking in Context: Intersectionality
Thinking in Context: Biological Influences
Intellectual Abilities
Fluid and Crystallized Intelligence
Intellectual Abilities Over the Adult Years
Cohort Effects in Intelligence
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Cognitive Development in Middle Adulthood
Attention
Memory
Processing Speed
Expertise
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Careers in Middle Adulthood
Job Satisfaction
Age Discrimination
Planning for Retirement
Thinking in Context: Lifespan Development
Apply Your Knowledge
Chapter Summary
Key Terms
Chapter 16 Socioemotional Development in Middle Adulthood
Psychosocial Development in Middle Adulthood
Is Midlife Characterized by Crisis?
Generativity Versus Stagnation
Seasons of Life
Search for Meaning
Sexuality
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
The Self
Self-Concept and Self-Esteem
Subjective Age
Perceived Control
Gender Identity
Life Satisfaction and Well-Being
Thinking in Context: Biological Influences
Thinking in Context: Intersectionality
Personality
Personality Stability and Change
Individual Differences in Stability and Change
Influences on Personality
Personality and Adjustment
Thinking in Context: Lifespan Development
Friendships and Romantic Relationships
Friendships
Marriage
Divorce
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Intergenerational Relationships
Parent–Child Relationships
Parents to Infants and Young Children
Parents to Adolescents
Parents to Adult Children
Grandparenthood
Grandparent–Grandchild Relationships and
Adjustment
Grandparents Raising Grandchildren
Relationships With Aging Parents
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Apply Your Knowledge
Chapter Summary
Key Terms
Lifespan Development at Work Part 7: Middle Adulthood
Part VIII Late Adulthood
Chapter 17 Physical and Cognitive Development in Late
Adulthood
Physical Development
Appearance
The Senses
Vision
Hearing
Smell and Taste
Cardiovascular, Respiratory, and Immune Systems
Motor Aging
The Aging Brain
Neural Compensation
Promoting Brain Health
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Atypical Brain Development: Dementia
Alzheimer’s Disease
Diagnosis of Alzheimer’s Disease
Progression of Alzheimer’s Disease
Risk Factors for Alzheimer’s Disease
Vascular Dementia
Parkinson’s Disease
Lewy Body Dementia
Race, Ethnicity, and Dementia
Thinking in Context: Biological Influences
Thinking in Context: Intersectionality
Health
Ages of Adulthood
Nutrition
Exercise
Chronic Illness
Arthritis
Osteoporosis
Injuries
Motor Vehicle Accidents
Falls
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Cognitive Development
Attention
Working Memory
Context, Task Demands, and Memory Performance
Emotion and Working Memory
Long-Term Memory
Language
Problem-Solving and Wisdom
Influences on Cognitive Change in Adulthood
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Apply Your Knowledge
Chapter Summary
Key Terms
Chapter 18 Socioemotional Development in Late Adulthood
Psychosocial Development
Self-Concept and Self-Esteem
Subjective Age
Reminiscence and Life Review
Ego Integrity
Personality
Sexuality
Religiosity
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Thinking in Context: Applied Developmental Science
Relationships
Friendships
Sibling Relationships
Marriage, Divorce, and Cohabitation
Marriage
Divorce and Remarriage
Cohabitation
Relationships With Adult Children and Grandchildren
Elder Maltreatment
Thinking in Context: Lifespan Development
Social Contexts
Changing Social World
Disengagement, Activity, and Continuity Theories
Socioemotional Selectivity Theory
Neighborhoods
Aging in Place
Residential Communities
Nursing Homes
Thinking in Context: Lifespan Development
Thinking in Context: Intersectionality
Retirement
Deciding to Retire
Transition to Retirement and Adjustment
Influences on Retirement Adjustment
Thinking in Context: Lifespan Development
Thinking in Context: Biological Influences
Apply Your Knowledge
Chapter Summary
Key Terms
Part 8 Lifespan Development at Work: Late Adulthood
Part IX Endings
Chapter 19 Death and Dying
Patterns of Mortality and Defining Death
Mortality and Life Expectancy
Leading Causes of Death
Thinking in Context: Intersectionality
Death and End-of-Life Issues
Defining Death
Advance Directives
Euthanasia
Physician-Assisted Suicide
Hospice
Thinking in Context: Lifespan Development
Conceptions of Death Across the Lifespan
Cultural Rituals and Views of Death
Children’s Understanding of Death
Adolescents’ Understanding of Death
Adults’ Understanding of Death
Thinking in Context: Lifespan Development
Dying and the Experience of Death
The Dying Process
Emotional Reactions to Dying
The Experience of One’s Death
The Dying Child
The Dying Adolescent
The Dying Adult
Thinking in Context: Applied Developmental Science
Bereavement and Grief
Grief Process
Models of Grieving
Contextual Influences on the Grief Process
Thinking in Context: Lifespan Development
Thinking in Context: Biological Influences
Adjusting to the Death of a Loved One
Losing a Spouse
Losing a Child
Losing a Parent
Bereavement in Childhood and Adolescence
Bereavement in Childhood
Bereavement in Adolescence
Thinking in Context: Lifespan Development
Apply Your Knowledge
Chapter Summary
Key Terms
Part 9: Lifespan Development at Work: Death
Glossary
References
Name Index
Subject Index
PREFACE
Lifespan Development: Lives in Context is the result of 25 years of
classroom discussions with students about the nature of
development during our lifetime. Many students find lifespan
development inherently interesting as they have observed,
experienced, or anticipate experiencing the topics we discuss.
Sharing observations and personal experiences is fun and engaging.
But sometimes our individual experiences don’t completely match
the theoretical and research conclusions we discuss. How do we
make sense of the differences? In class, as well as in this text, I adopt
a contextual perspective to help students understand variability in
development and to make sense of the growing body of findings in
lifespan development.
THEMES: CONTEXT AND APPLICATION
Lifespan Development: Lives in Context focuses on two key themes
that promote understanding of how humans develop through the
lifespan: the centrality of context and the applied value of
developmental science. These two themes are highlighted
throughout the text as well as in critical thinking features. In addition,
an accessible writing style helps students to grasp these complex
issues.
Contextual Perspective
The most central tenet of development is that it occurs in context. At
all points in life, human development is the result of dynamic
transactions among individuals, their physical, cognitive, and
socioemotional capacities, and the web of interacting contexts in
which they are immersed, such as family, peers, school,
neighborhood, society, culture, and history.
discusses these processes, emphasizing how
individual factors combine with the people, places, circumstances,
and time in which we live to influence development. A contextual
approach can provide the backstory to development and help us
Lives in Context
Lifespan Development:
understand why individuals vary. In addition, the emerging body of
research on intersectionality in development offers opportunities to
shed light on these complex processes and their role in
development.
This contextual theme is infused throughout the text and highlighted
specifically in critical thinking questions that appear at the end of
each section.
items ask
students to consider how biological factors, such as brain
development, physical development, and health, interact with
context to produce developmental outcomes.
items examine developmental theory and
themes, including applying Bronfenbrenner’s bioecological systems
theory to understand real-world problems, as well as the role of
culture in development. New to this third edition is an expansion of
discussions of diversity to consider intersectionality and its impact on
the development of children, adolescents, and adults.
calls attention to the ways in which race,
ethnicity, gender, sexual orientation, and socioeconomic status
overlap to determine opportunities and outcomes.
Thinking in Context: Biological Influences
Lifespan Development
Thinking in Context:
Thinking in
Context: Intersectionality
Applied Emphasis
The field of lifespan developmental science is unique because so
much of its content has immediate relevance to our daily lives.
Students may wonder: Do the first 3 years shape the brain for a
lifetime of experiences? Is learning more than one language
beneficial to children? Do people’s personalities change over their
lifetimes? Do adults go through a midlife crisis? How common is
dementia in older adulthood? Moreover, findings from lifespan
developmental science have been applied to inform social policies
that affect us all.
engages
students by exploring these and many more real-world questions.
This theme is integrated throughout the text and highlighted
specifically in a fourth type of end-of-section critical thinking
question.
items
ask students to apply the course content by considering cases,
designing research studies, and explaining the material to different
audiences and contexts. An
case appears at
the end of each chapter. These cases invite students to consider how
the content may be applied to a realistic scenario.
Lifespan Development: Lives in Context
Thinking in Context: Applied Developmental Science
Apply Your Knowledge
Accessible Writing Style
Having taught at a regional public university since 1996, I write in a
style intended to engage diverse undergraduate readers like my own
students. I attempt to write in the same voice as I teach, carefully
structuring sections to build explanations and integrating content
with examples that are relevant to students. I regularly use my own
texts in class, students work with me in preparing elements of each
text, and my students’ responses and learning guide my writing. My
experience teaching 12 courses during the COVID-19 pandemic in
Spring 2020 and the 2020–2021 academic year reinforced (for me)
the importance of accessible, concise textbooks. Like many faculty, I
was able to record only so many videos for my asynchronous classes,
so I relied heavily on my text, asynchronous discussion posts, and, for
the classes where available, SAGE Vantage, which enabled students
to interactively read the text.
PEDAGOGICAL FEATURES
My day-to-day experiences in the classroom have helped me to keep
college students’ interests and abilities at the forefront. Unlike many
textbook authors, I teach four classes each semester (and have done
so for 25 years). I taught my first online course in 2002. My daily
exposure to multiple classes and many students helps keep me
grounded in the ever-changing concerns and interests of college
students. I teach a diverse group of students. Some live on campus
but most commute. Most of my students are ages 18 to 24, but my
classes also include many so-called adult learners over the age of 24.
Many are veterans, a rapidly increasing population at my institution
with unique perspectives and needs. I have many opportunities to try
new examples and activities. I believe that what works in my
classroom will be helpful to readers and instructors. I use the
pedagogical elements of
in
my own classes and modify them based on my experiences.
Lifespan Development: Lives in Context
Critical Thinking Questions
In March 2020, my institution, like most in the United States,
suddenly transitioned to an entirely online campus. Like many faculty
across the country and world, I taught my four-course load entirely
online during the 2020–2021 academic year. Interacting with
students in many asynchronous courses (sprinkled with a small
handful of classes that met partially on Zoom) inspired the expansion
of my critical thinking feature
to include four
types of items that highlight critical themes in developmental
science.
items encourage readers to compare
concepts, apply theoretical perspectives, and consider applications of
the research findings presented. They appear at the end of each
main section within each chapter and highlight the following
previously described themes:
Thinking in Context
Thinking in Context
Thinking in Context: Biological Influences
Thinking in Context: Lifespan Development
Thinking in Context: Applied Developmental Science
Thinking in Context: Intersectionality
Case-Based Application
Applying Your Knowledge
Each chapter closes with a case scenario,
,
followed by in-depth questions that require students to apply their
understanding to address a particular situation or problem.
Learning Objectives and Summaries
Core learning objectives at the beginning of each section provide
clear goals for readers. The end-of-chapter summary returns to each
Learning Objective, recapping the key concepts presented in the
chapter related to that objective. In this third edition, many learning
objectives were revised to guide students' reading more closely. In
some chapters, learning objectives were added to break material
down into more manageable chunks for students as well as to
highlight new material.
Careers Related to Developmental Science
To say that my students are interested in careers—what they will do
after college—is an understatement. Students often don’t know
where to begin in considering possible careers. This third edition
includes a new applied feature,
,
which introduces students to over 35 careers that are related to or
benefit from an understanding of developmental science. Beginning
with a discussion of transferrable skills and fields, this feature
appears at the end of each part: Beginnings, Infancy, Early Childhood,
Middle Childhood, Adolescence, Early Adulthood, Middle Adulthood,
Late Adulthood, and Death.
Lifespan Development at Work
WHAT’S NEW IN LIFESPAN DEVELOPMENT:
LIVES IN CONTEXT, 3E?
I approached writing the third edition of
with three goals:
in Context
Lifespan Development: Lives
1. Increase the coverage of context, examine development
through an intersectional lens, and present an integrated view
of development.
I addressed this multifaceted goal by adding findings and
sections covering contextual and intersectional influences, as
available, throughout each chapter. A new section of Chapter 1
defines intersectionality and its value for understanding
development. I explain that the developmental science literature
on intersectionality is in its infancy but rapidly growing. I include
information about the interrelations of ethnicity, race, gender,
sexuality, socioeconomic status, and more, as available. The
critical thinking items
encourage students to examine development through an
intersectional lens.
Thinking in Context: Intersectionality
Also, I have removed thematic boxes from this third edition in
the interest of presenting an integrated view of development.
Boxed content, set apart from the text, can send the unintended
message that it is not as important as the text and can be
skipped. When boxed features cover themes such as the role of
culture, biology, or intersectionality, it may imply that these
concepts are not part of “normal” development. In this third
addition, context, culture, biology, intersectionality, and
gy
y
application are all infused throughout the text rather than
relegated to boxes. To call students’ attention to these critical
themes, an expanded set of
items focus on
biology, context, intersectionality, and application and appear
within each chapter, as previously described.
Thinking in Context
2. Update the text to include the most current research to date.
Our knowledge of human development is rapidly expanding. My
goal was to select, highlight, and integrate cutting-edge
findings with existing theory and research. Because new
research has its foundation in classic work, I integrate the two to
present a unified story of what is currently known in
developmental science. The third edition includes over 2,000
references published since 2018, including over 700 published
since 2020.
3. Increase coverage while retaining length.
My goal for this third edition was to increase coverage of
current research and expand several sections in each chapter to
better cover relevant developmental issues (such as the opioid
epidemic, spirituality, civic development and critical
consciousness, and the experience of discrimination). Despite
these additions, the overall length of most chapters has
remained the same. I worked to streamline discussions by
carefully integrating new material with old, selecting the most
appropriate examples and details to include, and paring down
excess.
Below I list some of the major revisions reflected in this third edition
of
. Each chapter contains
many other changes that are not documented here. It is my hope
that this volume will improve instructors’ and students’ experiences
in and out of class—and that students will be inspired to apply the
findings of developmental science to their lives.
Lifespan Development: Lives in Context
Chapter 1
New learning objective: 1.6 Describe the field of applied
developmental science and the role of intersectionality in
development.
New section:
Sociohistorical Context
Cultural Context
Ethical Issues in Studying Lifespan Human Development
Applied Developmental Science and Intersectionality
Dynamic Systems Theory
Reorganized/substantive revisions:
History Graded Influences
Bronfenbrenner’s Bioecological Systems Theory
Research Ethics
Chapter 2
New learning objectives:
2.4 Compare and contrast characteristics and outcomes of
adoption, transracial adoption, and international adoption.
2.5 Summarize prenatal diagnostic methods and how
genetic disorders may be treated prenatally.
2.6 Provide an introduction to the field of behavior genetics,
including representative findings.
New section:
Adoption
Prenatal Diagnosis
Assisted Reproductive Technology and Sex Selection
Gene–Environment Interactions
Reorganized/substantive revision: Epigenetic Framework
Chapter 3
New learning objectives:
3.3 Compare the influence of maternal and paternal
characteristics on prenatal development.
3.4 Identify barriers to prenatal care and intersectional
influences on access to prenatal care.
3.6 Examine risks for low birthweight, characteristics of lowbirthweight infants, and ways of supporting positive
outcomes of low-birthweight infants.
New section:
Opioids
Contextual Factors and Teratogens
Maternal and Paternal Characteristics and Prenatal
Development
Low-Birthweight Infants: Preterm and Small-for-Date Babies
Contextual and Cultural Influences on Prenatal Care
Lifespan Development at Work: Introduction to Careers;
Genetic Counselor; Nurse Midwife; Doula
Reorganized/substantive revisions:
Maternal Illness
Maternal Emotional Well-Being
Cultural Influences on Development
New Apply Your Knowledge case
Chapter 4
New learning objective: 4.2 Examine threats to infant and
toddler health.
New section:
Infant Mortality
SIDS
Reorganized/substantive revisions:
Body Growth
Growth Faltering
Touch
Failure to Vaccinate
Chapter 5
New opening vignette
New learning objectives:
5.2 Evaluate Piaget’s sensorimotor reasoning stage in light
of research evidence.
5.6 Compare and contrast influences on language
development.
New section:
Evaluating Sensorimotor Reasoning
Culture and Cognitive Development
Contexts for Learning: Screens and Digital Media
Child Care and Cognitive Development
Poverty and Cognitive Development
Infant Gesture and Sign Language
Language Development in Bilingual Infants
Language Development in Deaf Infants
Cultural Differences in Infant-Directed Speech
New Apply Your Knowledge case
Chapter 6
New section:
Exposure to Early Life Stress
Maternal Depression and Attachment
Father–Infant Attachment
Lifespan Development at Work: Child Care Director; Social
Worker; Pediatric Nurse; Pediatrician
Reorganized/substantive revisions:
Social Interaction and Emotional Development
Emotional Socialization
Context and Goodness of Fit
Cultural Variations in Attachment Classifications
Chapter 7
New learning objective: 7.2 Examine the influence of nutrition,
physical activity, sleep, and screen use on young children’s
health as well as risks to health.
New section:
Health: Physical Activity; Sleep; Nutrition and Eating Habits
Health Threats: Screen Use; Illness and Toxins; Unintended
Injuries
Language: Bilingual Language Learning; Race,
Socioeconomic Status, and Language Development
Suggestibility
Reorganized/substantive revisions:
Growth
Motor Development
Private Speech
Chapter 8
New section:
Transgender Gender Identity
Reducing Gender Stereotyping
Culture and Play
Lifespan Development at Work: Early Childhood Educator;
Speech/Language Pathologist; Developmental Psychologist;
Toy and Media Research
Reorganized/substantive revisions:
Moral Development (from Chapter 7)
Emotional Development
Gender Stereotypes, Gender Differences, and Gender
Development
Play and Peer Relationships in Early Childhood
Chapter 9
New learning objectives:
9.2 Examine health behaviors and concerns during middle
childhood, including physical activity, injury, and obesity.
9.3 Compare common developmental disabilities and
discuss the relevance of contextual influences for disability.
New section:
Developmental Disabilities, with subsections on AttentionDeficit/Hyperactivity Disorder, Autism Spectrum Disorder,
Specific Learning Disorder, and Context and Disability: Race
and Socioeconomic Status
Brain Development
Adrenarche
Physical Activity in Middle Childhood
Childhood Injuries and Mortality
Context and Cognition
Bilingual Language Learning
Approaches to Education
Access to Digital Technology and Learning
Implications of Cognitive Developmental Theory for
Education
Implications of Information Processing Theory for Education
Chapter 10
Revised opening vignette
New learning objective: 10.3 Discuss gender differences, gender
stereotypes and beliefs, and gender identity in middle
childhood.
New section:
Gender Development
Parental Incarceration
Parental Deployment
Body Image
Only Children
Lifespan Development at Work: Elementary Education;
Special Education; Child Life Specialist; Applied Behavior
Analyst; School Psychologist
Reorganized/substantive revisions:
Moral Development (from Chapter 9)
Risk and Resilience in Middle Childhood (revised and
expanded; was: Common Socioemotional and
Developmental Problems in Middle Childhood)
Chapter 11
Updated opening vignette
New learning objective: 11.2 Identify influences on health and
recommendations to improve adolescents’ health.
New section:
Experience and the Adolescent Brain
Social Cognition
Adolescent Health
Adolescent Employment
Reorganized/substantive revisions:
Pubertal Timing and Adolescent Development
Biological and Contextual Influences on Pubertal Timing
g
Brain Development and Behavior
g
New Apply Your Knowledge case
Chapter 12
New learning objective: 12.2 Describe the progression of and
influences on the development of moral reasoning, civic
engagement, and critical consciousness.
New section:
Gender Intensification and Transgender Identity
Spirituality and Religiosity
Moral and Civic Development in Adolescence
Peers, Social Media, and Cyberbullying
Binge Eating Disorder
Sexuality Education
Lifespan Development at Work: Secondary Education;
School Counselor; Recreation Worker; Intervention
Research; Applied Developmental Psychologist
Reorganized/substantive revisions:
Self-Esteem
Ethnic–Racial Identity
Parenting
Dating
Chapter 13
New learning objective: 13.2 Discuss common health concerns
and the effects of physical activity in early adulthood.
New section:
Students With Developmental Disabilities
Intersectionality and the Workplace
Reorganized/substantive revisions:
Theories of Aging: What Causes Aging? (from Chapter 15)
Not Attending College (was Forgotten Third)
Transition to Work
Work–Life Balance (replaces Work and Family)
Chapter 14
New learning objective: 14.3 Review the nature of sexual activity
in early adulthood and the problem of sexual assault.
New section:
Sexuality
Attachment
Lifespan Development at Work: ESL Teacher; Substance
Counselor; Clinical and Counseling Psychologist; Professor;
Resident Director
Reorganized/substantive revisions:
Emerging Adulthood (from Chapter 13)
Identity Versus Role Confusion, revised to include
subsections on Moral Identity, Religious Identity, Political
Identity, Gender and Sexual Identity, and Racial-Ethnic
Identity
Becoming a Parent
Nonmarital Childbearing
Gay and Lesbian Parents
Chapter 15
New learning objective: 15.5 Discuss career-related concerns of
middle-aged adults, including influences on job satisfaction,
experiences with age discrimination, and planning for
retirement.
New section:
Mortality
Cohort Effects in Intelligence
Age Discrimination
Reorganized/substantive revisions:
Stress
Planning for Retirement
Job Satisfaction
Chapter 16
New learning objectives:
16.3 Analyze patterns of stability and change in personality
in middle adulthood.
16.4 Examine friendship and spousal relationships in middle
adulthood.
16.5 Contrast adults’ relationships and roles as parents to
young children, adolescents, and adults; as grandparents;
and as parents to adult children.
New section:
Personality
Search for Meaning
Subjective Age
Perceived Control
Divorce
Lifespan Development at Work: Marriage and Family
Therapist; Physical Therapist and Assistant; Occupational
Therapist and Assistant; Human Resources; Health
Psychologist
Reorganized/substantive revisions:
Is Midlife Characterized by Crisis?
Expanded and broke into two sections: Friendship and
Romantic Relationships and Intergenerational Relationships
Sexuality (from Chapter 15)
Expanded and updated Parent–Child Relationships to
include subsections on Parenting Infants, Parenting
Adolescents, and Parenting Adult Children
Grandparents
Chapter 17
Revised opening vignette
New section:
Race, Ethnicity, and Dementia
Ages of Adulthood
Reorganized/substantive revisions:
Exercise
Atypical Brain Aging (was Dementia)
Updated and expanded The Aging Brain to include Neural
Compensation, Promoting Brain Health
Chapter 18
New section:
Friendships
Lifespan Development at Work: Audiologist; Geriatric Nurse;
Geriatrician; Geropsychologist; User Design and Usability
Reorganized/substantive revisions:
Sexuality
Socioemotional Selectivity Theory
Aging in Place
Retirement: Deciding to Retire; Transition to Retirement and
Adjustment
Chapter 19
New learning objectives:
19.1 Identify the leading causes of death and patterns of
mortality and life expectancy.
19.6 Describe patterns of adjustment after bereavement.
New section:
Mortality and Life Expectancy
Death and End-of-Life Issues
Lifespan Development at Work: Grief Counselor; Hospice
Services
Reorganized/substantive revisions:
Cultural Rituals and Views of Death
Expanded into a new section: Adjustment After the Loss of a
Loved One
In the electronic edition of the book you have purchased, there are
several icons that reference links (videos, journal articles) to
additional content. Though the electronic edition links are not live, all
content referenced may be accessed at https://vantage.sagepub.com
. This URL is referenced at several points throughout your electronic
edition.
ACKNOWLEDGMENTS
This book has benefitted from the input of many bright, enthusiastic,
and generous people. I am fortunate to work with a talented team at
SAGE, and I am grateful for their support. I thank Lara Para for her
steadfast encouragement, Katherine Hepburn for her marketing
wizardry, and Reid Hester for bringing me to the SAGE family.
Michele Sordi encouraged me to write the first edition of this text,
and I am forever grateful for her confidence. Emma Newsom’s talent
in managing the many moving pieces keeping this project (and me!)
on track is beyond par. Thank you! Jessica Miller provided a patient,
supportive ear and invaluable guidance in making the many
decisions involved in writing this book.
I am especially appreciative of those who have shared their feedback
and helped me to improve this third edition. Lauren Schwarz
provided invaluable assistance in a variety of capacities, from
brainstorming and literature searches to organization,
recordkeeping, and a range of creative (and frequently tedious) tasks.
I thank Gabrielle Johnson for her meticulous review and update of
the glossary and her contributions to the careers feature, including
brainstorming, gathering, and organizing the data. Thanks, Gabby,
for your creativity and positive vibes.
I thank my students for their engagement in and out of class. Our
discussions inform these pages. I am especially appreciative of those
who have shared their feedback. Thank you to the many instructors
who have reviewed and provided feedback on these chapters.
Finally, I thank my family, especially my parents for their unwavering
support. Most of all, I am thankful for the support of my husband,
Fred, for his optimism, patience, encouragement, and love. There’s no
one I’d rather quarantine with.
SAGE thanks the following expert reviewers, who provided detailed
recommendations in their areas of expertise, with a focus on
multicultural and cross-cultural findings and diversity in
development:
Cassendra Bergstrom completed her PhD in Educational Psychology
at the University of Northern Colorado (UNC), where she is now an
assistant professor. She held a post-doctoral research position
working on a National Science Foundation grant through the Math
and Science Teaching Institution, also at UNC. Dr. Bergstrom’s
research focuses on the intersection of motivation and learning
environments, with a recent focus on equity. Her publications and
presentations stem from research projects on the topics of
transformative experience, goal orientation, and problem-based
learning (PBL) environments. Dr. Bergstrom currently teaches
undergraduate psychology courses, as well as graduate courses in
educational psychology.
Flora Farago is an assistant professor of Human Development and
Family Studies at Stephen F. Austin State University, with a
background in developmental psychology and early childhood
education. Her teaching and research interests center around
children's prejudice and stereotype development, and anti-bias
curricula surrounding race and gender. Dr. Farago is particularly
interested in the link between research and community activism. She
collaborates with colleagues and organizations nationally and
internationally, including the Indigo Cultural Center, the Jirani Project,
and the Girl Child Network, to promote racial and gender equity.
Jessamy Comer is a lecturer at Rochester Institute of Technology in
Rochester, New York. She has been teaching developmental
psychology for over a decade, as well as many other undergraduate
and graduate courses. Her area of research interest and
specialization is in parent–child relationships, particularly during
adolescence. She earned her BA degree in psychology from Baylor
University in Waco, Texas, and she earned her MA and PhD in
developmental psychology from the University of Rochester in
Rochester, New York. She is also a recipient of the Helen and Vincent
Nowlis Award for Excellence in Teaching.
Kathy Erickson is a University of Arizona faculty member teaching in
the Human Services and Family Studies departments. Professor
Erickson’s master’s degree is in holistic psychology, with an emphasis
in mindfulness and addiction. She has an undergraduate degree in
counseling with a minor in holistic education. For two decades, Kathy
worked with adolescents in education and social services settings.
She introduced students to biofeedback and mindfulness techniques
to help them develop mechanisms to alleviate and manage stress.
She is committed to the value of integrating mindfulness throughout
all aspects of one's life, as well as in the courses she teaches.
Merranda Romero Marín is an associate professor in the
Department of Family and Consumer Science at New Mexico State
University where she teaches courses ranging from lifespan
development to multicultural family life education and clinical
courses in marriage and family therapy. She is a licensed psychologist
and a licensed marriage and family therapist specializing in the
treatment of posttraumatic stress disorder (PTSD). Her areas of
research include understanding the impact of poverty on children
and family systems, the effects of trauma on family and community
systems, multicultural counseling, and individual and family
resilience.
Robert S. Weisskirch, MSW, PhD, is a professor of human
development in the Liberal Studies Department at California State
University, Monterey Bay. His research interests focus on language
brokering, ethnic identity and acculturation, developmental
perspectives on romantic relationships, how technology affects
relationships (i.e., parent–adolescent relationships, sexting, and
romantic relationships), and pedagogy of adolescent development.
He received his PhD in human development from the University of
California, Davis, a Master of Social Work from San Diego State
University, and a Multiple Subjects Teaching Credential and BA in
psychology from the University of California, Irvine.
Sarah Savoy is an associate professor of psychology at Stephen F.
Austin State University, where she teaches courses in developmental,
social, and health psychology. Her research concerns topics such as
social and cognitive processes that contribute to the development of
disordered eating as well as stigma related to eating disorders and
obesity.
SAGE wishes to thank the following reviewers for their valuable
contributions to the development of this third edition:
Carla Bluhm, College of Coastal Georgia
Kelly Champion, Northern Illinois University
Naomi Ekas, Texas Christian University
Mike Figuccio, CUNY Queensborough
Janice Gallagher, Ivy Tech Community College
Surinder Gill, California State University, Sacramento
Jessica Grady, Pacific University
David Hanbury, Averett University
Linda Krajewski, University of Redlands
Alan Meca, Old Dominion University
Jennifer Butler Moss, Emporia State University
Michelle Pilati, Rio Hondo College
Carolynn Pravatta, Collin College
Katie Purswell, Texas State University
Nina Slota, Fairmont State University
Catherine Steinbock, Eastern Wyoming College
Elizabeth Tinsley, Marquette University
Katherine Volk, Lesley University
SAGE also expresses special appreciation to reviewers of prior
editions whose thoughtful feedback has strengthened and lives on in
the current edition:
Marita Andreassen, Inland Norway University of Applied
Sciences
Linda Aulgur, Westminster College
Stephen Baker, Saint Francis University
Cassendra Bergstrom, University of Northern Colorado
Jamie Borchardt, Tarleton State University
Ashley Cosentino, Chicago School of Professional Psychology
Christine Weinkauff Duranso, California State University–San
Bernardino
Robert Gall, Grace University
Theresa Garfield, Texas A&M University–San Antonio
Jerry Green, Tarrant County College
Janice Hargrove-Freile, Lonestar State University
Erin Harmeyer, Louisiana State
Crystal Harris, Governors State University
Jerry Haywood, Fort Valley State University
Cynthia Jacox, Alamo College
Benjamin Jeppsen, University of Nevada, Reno
Cristina Joes-Kampfner, Eastern Michigan University
Lakitta Johnson, Jackson State University
Jeff Kellogg, Marian University Indianapolis
Nancy Lamphere, Caldwell Community College & Technical
Institute
Robyn Long, Baker University
Geraldine Lotze, Virginia Commonwealth University
Merranda Marín, New Mexico State University
Robert Martinez, Alamo College
Robert Martinez, University of the Incarnate Word
Maribeth Palmer-King, SUNY Broome
Melanie Palomares, University of South Carolina
Kathy Phillippi-Immel, University of Wisconsin Colleges
Gary Popoli, Stevenson University
Martha Ravola, Alcorn University
Mary Schindler, Sonoma State University
Brittney Schrick, University of Arkansas Cooperative Extension
Service
Staci Simmelink-Johnson, Walla Walla Community College
Patrick Smith, Virginia Community College
Brooke Spangler-Cropenbaker, Miami University
Tara Stoppa, Eastern University
Marcia Tipton, Milwaukee Area Technical College
Debra Tower, University of Oklahoma
Bridget Walsh, University of Arkansas Cooperative Extension
Service
Shauna Nefos Webb, Milligan College
ABOUT THE AUTHOR
Tara L. Kuther
is professor of psychology at Western Connecticut State
University, where she has taught courses in child, adolescent,
and adult development since 1996. She earned her PhD in
developmental psychology at Fordham University. Dr. Kuther is
fellow of the Society for the Teaching of Psychology (APA,
Division 2), has served in various capacities in the Society for the
Teaching of Psychology and Society for Research on
Adolescence, and is the former chair of the Teaching Committee
for the Society for Research in Child Development. In addition to
the award-winning book
, Dr. Kuther is also the author of
;
; and
. Her research
interests include social cognition and risky activity in
adolescence and adulthood. She is also interested in promoting
undergraduate and graduate students’ professional
development. Her books,
and
(with Robert Morgan), are intended to help students navigate
the challenges of pursuing undergraduate and graduate degrees
in psychology.
Lifespan Development: Lives in
Context
Child and Adolescent
Development in Context Adolescence in Context Lifespan
Development in Context: A Topical Approach
The Psychology Major’s Handbook
Careers in Psychology: Opportunities in a Changing World
PART I FOUNDATIONS OF LIFESPAN
HUMAN DEVELOPMENT
1 UNDERSTANDING HUMAN DEVELOPMENT:
APPROACHES AND THEORIES
iStock/Hispanolistic
Think back over your lifetime. How have you grown and changed through the years? Do your parents
describe you as a happy baby? Were you fussy? Do you remember your first day of kindergarten? What
are some of your most vivid childhood memories? Did you begin puberty early, late, or at about the
same time as others your age? Were your adolescent years a stressful time? What types of changes do
you expect to undergo in your adult years? Where will you live? Will you have a spouse? Will you have
children? What career will you choose? How might these life choices and circumstances influence how
you age and your perspective in older adulthood? Will your personality remain the same or change over
time? In short, how will you change over the course of your lifespan?
WHAT IS LIFESPAN HUMAN DEVELOPMENT?
LEARNING OBJECTIVE
1.1 Outline five principles of the lifespan developmental perspective.
This is a book about lifespan human development—the ways in which people grow, change, and stay
the same throughout their lives, from conception to death. When people use the term development,
they often mean the transformation from infant to adult. However, development does not end with
adulthood. We continue to change in predictable ways throughout our lifetime, even into old age.
Developmental scientists study human development seeking to understand these lifetime patterns of
change.
Table 1.1 illustrates the many phases or stages of life through which we progress from conception to
death. The stages may have different labels and different sets of developmental tasks, but all have value
and influence each other. The changes that we undergo during infancy, for instance, influence how we
experience later changes, such as those during adolescence and beyond. Each stage of life is important
and accompanied by its own demands and opportunities.
Table 1.1 Stages in Human Development
Approximate Description
Age Range
Prenatal
Conception
Shortly after conception, a single-celled organism grows and multiplies.
to birth
This is the period of the most rapid physical development as basic body
structures and organs form, grow, and begin to function.
Infancy and Birth to 2
The newborn is equipped with senses that help it to learn about the
toddlerhood years
world. Physical growth occurs and motor, perceptual, and intellectual
skills develop. Children show advances in language comprehension and
use, problem- solving, self-awareness, and emotional control. They
become more independent and interested in interacting with other
children and form bonds with parents and others.
Early
2 to 6 years
Children grow steadily, their muscles strengthen, and they become better
childhood
at coordinating their bodies. Memory, language, and imagination
improve. Children become more independent and better able to regulate
their emotions. Family remains children’s primary social tie, but other
children become more important and new ties to peers are established.
Life Stage
Approximate
Description
Age Range
Middle
6 to 11 years Growth slows, but strength and athletic ability increase dramatically.
childhood
Children show improvements in their ability to reason, remember, read,
and use arithmetic. As children advance cognitively and gain social
experience, they understand themselves in more complex ways
compared with younger children. As friendships develop, peers and
group memberships become more important.
Adolescence 11 to 18
Adolescents’ bodies grow rapidly. They become physically and sexually
years
mature. Although some immature thinking persists, adolescents can
reason in sophisticated and adult-like ways. Adolescents are driven to
learn about themselves and begin the process of discovering who they
are, apart from their parents. Peer groups increase in importance.
Early
18 to 40
Physical condition peaks and then shows slight declines with time.
adulthood
years
Lifestyle choices play a large role in influencing health. Most young
adults join the workforce, marry or establish a long-term bond with a
spouse, and become parents. The timing of these transitions varies.
Adolescents in Western industrialized societies often experience an
extended transition to adulthood (called emerging adulthood), spanning
from ages 18 to 25, and as late as age 29.
Middle
40 to 65
In middle adulthood, people notice changes in their vision, hearing,
adulthood
years
physical stamina, and sexuality. Basic mental abilities, expertise, and
practical problem-solving skills peak. Career changes and family
transitions require that adults continue to refine their understandings of
themselves. Adults help children to become independent, adapt to an
empty nest, and assist elderly parents with their own health and personal
needs.
Late
65 years and Most older adults remain healthy and active. Reaction time slows, and
adulthood
beyond
most older adults show a decline in some aspects of memory and
intelligence, but an increase in expertise and wisdom compensates for
losses. Most older adult friendships are old friendships, and these tend to
be very close and a source of support. Adults adjust to retirement,
changes in health, and personal losses (such as the death of a loved one),
as well as search for meaning in their lives.
Death
Death itself is a process entailing the stopping of heartbeat, circulation,
breathing, and brain activity. A person’s death causes changes in his or
her social context—family members and friends must adjust to and
accept the loss.
Life Stage
Change is perhaps the most obvious indicator of development. The muscle strength and coordination
needed to play sports increases over childhood and adolescence, peaks in early adulthood, and begins
to decline thereafter, declining more rapidly from middle to late adulthood (Gabbard, 2018). There also
are ways in which we change little over our lifetimes. Some personality traits are highly stable over the
lifespan, so that we remain largely the “same person” into old age (Schwaba & Bleidorn, 2018; Wortman
et al., 2012).
Lifespan human development can be described by several principles. Development is: (1)
multidimensional, (2) multidirectional, (3) plastic, (4) influenced by multiple contexts, and (5)
multidisciplinary (Baltes et al., 2006; Overton & Molenaar, 2015).
Development Is Multidimensional
Consider the many changes that mark each period of development and it is apparent that development
is
. That is, development includes changes in multiple areas or domains of
development. Physical development refers to body maturation and growth, such as body size,
proportion, appearance, health, and perceptual abilities. Cognitive development refers to the
maturation of thought processes and the tools that we use to obtain knowledge, become aware of the
world around us, and solve problems. Socioemotional development includes changes in personality,
emotions, views of oneself, social skills, and interpersonal relationships with family and friends. These
areas of development overlap and interact. The onset of walking precedes advances in language
development in infants in the United States and China (He et al., 2015; Lüke et al., 2019). Brain
multidimensional
maturation, a physical development, underlies advances in cognitive development, which might enable
adolescents to become better at understanding their best friend’s point of view and show more
prosocial helpful behavior (Tamnes et al., 2018). In turn, adolescents might become more empathetic
and sensitive to their friends’ needs and develop a more mature friendship, influencing socioemotional
development (Tamnes et al., 2018). Figure 1.1 illustrates how the three areas of development interact.
Description
Figure 1.1 Domains of Development
Sources: iStock/Essentials; iStock/Signature; Jupiter/Pixland/Thinkstock
Development Is Multidirectional
Development is commonly described as a series of improvements in performance and functioning, but
in fact development is
, meaning that it consists of both gains and losses, growth and
decline, throughout the lifespan (Baltes et al., 2006; Overton & Molenaar, 2015). For example, infants are
born with a stepping reflex, an innate involuntary response in which they make step-like movements
when held upright over a horizontal surface (for more on infant reflexes, see Chapter 4). The stepping
reflex disappears by about 2 months but reemerges as a voluntary action at 8 to 12 months of age as
infants begin walking with support (Adolph & Franchak, 2017). Throughout life, there is a shifting
balance between gains, improvements in performance (common early in life), and declines in
performance (common late in life) (Baltes et al., 2006; Zacher et al., 2019). At all ages individuals can
compensate for losses by improving existing skills and developing new ones (Boker, 2013). The speed at
which people think tends to slow in late adulthood, but increases in knowledge and experience enable
older adults to compensate for the loss of speed when completing everyday tasks (Krampe & Charness,
2018; Margrett et al., 2010).
multidirectional
We are born with a stepping reflex, an innate involuntary response. When
this infant is held under the arms in a standing position on a flat surface, his
legs move in a stepping motion.
Phanie/Alamy Stock Photo
Development Is Plastic
Development is characterized by plasticity: It is malleable, or changeable. Frequently the brain and body
can compensate for illness and injury. In children who are injured and experience brain damage, for
instance, other parts of the brain may take on new functions (Petranovich et al., 2020). The plastic nature
of human development allows people to modify their traits, capacities, and behavior throughout life
(Baltes et al., 2006; Overton & Molenaar, 2015). Older adults who have experienced a decline in balance
and muscle strength can regain and improve these capabilities through exercise (McAuley et al., 2013;
Sañudo et al., 2019). Plasticity tends to decline as we age, but it does not disappear entirely. Short
instruction, for instance, can enhance the memory capacities of very old adults, but less so in younger
adults (Brehmer et al., 2012; Willis & Belleville, 2016). Plasticity makes it possible for individuals to adjust
to change and to demonstrate resilience, the capacity to adapt effectively to adverse contexts and
circumstances (Luthar et al., 2015; Masten, 2016). The brain naturally adapts to a lifetime of sensory
experiences in order to portray the world around us efficiently and accurately as we age into older
adulthood (Moran et al., 2014; Zanto & Gazzaley, 2019).
Some plasticity is retained throughout life. Practicing athletic activities can
help older adults rebuild muscle and improve balance.
Reuters/Mariana Bazo
Development Is Influenced by Multiple Contexts
Context refers to where and when a person develops. Context encompasses many aspects of the
physical and social environment, including family, neighborhood, country, and historical time period. It
includes intangible factors, characteristics that are not visible to the naked eye, such as values, customs,
ideals, and culture. To understand individuals’ development, we must look at their context, including the
subtle, less easily viewed factors.
Were you encouraged to be assertive and actively question the adults around you, or were you expected
to be quiet and avoid confrontation? How large a part was spirituality or religion in your family’s life?
How did religious values shape your parents' childrearing practices and your own values? How did your
family’s economic status affect your development? These questions examine a critical context for our
development: home and family. However, we are embedded in many more contexts that influence us,
and that we influence, such as peer group, school, neighborhood or community, and culture. Our
development plays out within the contexts in which we live, a theme that we will return to throughout
this book.
Sociohistorical Context
The multitude of contextual factors that interact over the life course can be organized into three
categories: age-graded influences, history-graded influences, and non-normative influences (Elder &
George, 2016; Elder et al., 2016).
Age-Graded Influences.
Age-graded influences are closely tied to chronological age and are largely predictable. Most individuals
walk at about a year of age and reach puberty in early adolescence. Similarly, most women reach
menopause in the late 40s or early 50s. Age-graded influences tend to be most influential early and late
in life. Although these influences are often tied to biology, social milestones can also form age-graded
influences. Most people in the United States enter school at about 5 years of age, graduate high school
and enter college at about age 18, and retire during their 60s. Some age-graded influences are context
dependent. Adolescents in suburban and rural contexts commonly get driver’s licenses at age 16, but
this may not be true of adolescents in urban settings where driving may be less common.
History-Graded Influences.
History-graded influences refer to how the time period in which we live and the unique historical
circumstances of that time period affect our development. History-graded influences include wars,
epidemics, advances in science and technology, and economic shifts such as periods of depression or
prosperity (Baltes, 1987). The COVID-19 pandemic of 2020 may shape individuals’ health behaviors, such
as by wearing face coverings, standing further away from others, and refraining from particular social
behaviors, such as handshakes and hugs. School closures during the pandemic posed risks to children’s
and adolescents’ academic and social development as well as their mental health (Golberstein et al.,
2020; Lee, 2020). Even temporary changes, such as these, are contextual influences that shape our world
and our development. The effect of historical events on development depends in part on when they
occur in a person’s life (Elder et al., 2015). Older adults may experience the COVID-19 pandemic
differently than younger people, given their lifelong experiences as well as their heightened risk for
infection (Pfefferbaum & North, 2020). For many older adults, the pandemic is a period of great
loneliness.
The COVID-19 pandemic is an example of a sociohistorical influence that
contributes to cohort, or generational, differences in development.
iStock/kali9
Contextual influences tied to specific historical eras explain why a generation of people born at the same
time, called a cohort, is similar in ways that people born at other times are different. Adults who came of
age during the Great Depression and World War II are similar in some ways that make them different
from later cohorts; they tend to have particularly strong views on the importance of the family, civic
mindedness, and social connection (Rogler, 2002). Yet the same historical event may be experienced
differently by successive cohorts relatively close in age, reflecting the fact that they are in different life
stages, with different social roles, levels of maturity, and life experiences. Researchers examined the
influence of the Great Depression (1929–1941) and World War II (1939–1945) on two cohorts of
California-born Americans born just 8 years apart in Oakland and Berkeley, and who were followed from
childhood to older adulthood, over a 70-year period (Elder & George, 2016).
Boys in the older Oakland cohort (born in 1920–1921) were children during the affluent 1920s, a time of
economic growth in California, and they experienced a prosperous and relatively stress-free childhood.
They entered adolescence during the Great Depression, a period of severe economic stress in which
unemployment skyrocketed and people’s savings were depleted. As adolescents during the Great
Depression, the Oakland boys tended to behave responsibly and assist their families in coping, such as
by working jobs outside the home, which enhanced their independence and sense of responsibility and
reduced their exposure to family stress. The Oakland cohort completed high school just prior to the
onset of World War II and over time nearly all the young men entered the armed forces.
Unlike the Oakland cohort, boys in the Berkeley Guidance Study (born in 1928–1929) experienced the
Great Depression in early childhood, at a time when they were vulnerable and very dependent on family.
The Berkeley cohort entered adolescence during World War II, a period of additional economic and
emotional stress resulting from empty households (as both parents worked to support the war effort)
and the military service and war trauma of older brothers. As adolescents, the Berkeley boys’ outlook
was bleaker than the boys in the Oakland cohort. Berkeley boys experienced emotional difficulties, poor
attitudes toward school, and less hope, self-direction, and confidence about their future.
However, the Berkeley boys were not doomed. Their outlook improved in adulthood, largely because of
their experiences in military service. Three-quarters of the Berkeley sample served in the military
between 1945 and the end of the Korean War in the early 1950s. The most disadvantaged young men
tended to join the military early, and early entry into the military predicted personal growth because of
opportunities, such as structure, travel, and to take advantage of the GI Bill of Rights, which enabled
them to expand their education and acquire new skills after the war.
These two cohorts of young people offer striking examples of how sociohistorical context influences
development. Although boys in both cohorts tended to develop into mature productive adults, they
took different paths. Context always plays a role in development—not only in times of social upheaval
but every day and for every generation.
Take a moment to think about what role larger historical events have played in your development.
Consider the Black Lives Matter movement, begun in 2013; the legalization of same-sex marriage in
2015; the school shooting in Newtown, Connecticut, in 2012; the election of the first African American
president of the United States in 2008; and the terrorist attacks of September 11, 2001. How have
historical events influenced you and those around you? Can you identify ways in which, because of
historical events, your cohort may differ from your parents’ cohort? Your grandparents’ cohort?
Non-Normative Influences.
Whereas age-graded and history-graded influences are common to all people, or all members of a
cohort, individuals also have experiences that are unique to them.
are
experiences or events that happen to a person or a few people. Examples of non-normative influences
include experiencing the death of a parent in childhood, widowhood in early adulthood, winning the
lottery, or illness. Non-normative events are not predictable and are not easily studied, as they are not
experienced by most people—and the nature of non-normative events varies widely. With age, nonnormative influences become more powerful determinants of development.
Non-normative influences
Cultural Context
Like sociohistorical context, the cultural context is a broad influence on the development of all people at
all ages in life. Culture refers to a set of customs, knowledge, attitudes, and values that are shared by
members of a group and are learned early in life through interactions with group members (Markus &
Kitayama, 1991). We are immersed in culture, which influences all of our contexts and includes the
processes used by people as they make meaning or think through interactions with group members
(Mistry et al., 2016; Yoshikawa et al., 2016).
cross-cultural research
Early studies of culture and human development took the form of
, comparing
individuals and groups from different cultures to examine how these universal processes worked in
different contexts (Mistry & Dutta, 2015). Yet research that defines normative development based on
Western samples leads to narrow views of human development that do not consider the variety of
contexts in which people live. At the extreme, differences in human development within other cultural
groups might be viewed as abnormal and harmful (Cole & Packer, 2015).
Most classic theories and research on human development are based on Western samples because
researchers once believed that the processes of human development were universal. More recent
observations suggest that development varies dramatically with cultural context (Keller, 2017). Consider
milestones, such as the average age that infants begin to walk. In Uganda, infants begin to walk at about
10 months of age, in France at about 15 months, and in the United States at about 12 months. These
differences are influenced by parenting practices that vary by culture. African parents tend to handle
infants in ways that stimulate walking, by playing games that allow infants to practice jumping and
walking skills (Hopkins & Westra, 1989; Super, 1981). The cultural context in which individuals live
influences the timing and expression of many aspects of development, even physical developments,
such as walking, long thought to be a matter of biological maturation (Mistry, 2013). Applying principles
of development derived from Western samples to children of other cultures may yield misleading
conclusions about children’s capacities (Keller, 2017).
cultural research
There is a growing trend favoring
, which examines how culture itself influences
development, over cross-cultural research, which simply examines differences across cultures (Cole &
Packer, 2015). Cultural research examines development and culture as fused entities that mutually
interact, with culture inherent in all domains of development and a contributor to the context in which
we are embedded, transmitting values, attitudes, and beliefs that shape our thoughts, beliefs, and
behaviors (Miller et al., 2020; Mistry & Dutta, 2015). The shift toward cultural research permits the
examination of the multiple subcultures that exist within a society (Oyserman, 2016, 2017). North
American culture is not homogeneous; many subcultures exist, defined by factors such as ethnicity (e.g.,
African American, Asian American), religion (e.g., Christian, Muslim), geography (e.g., southern,
midwestern), and others, as well as combinations of these factors. Current trends in cultural research
document diversity and emphasize understanding how the historical, cultural, and subcultural contexts
in which we live influence development throughout our lives.
Developmental Science Is Multidisciplinary
Psychologists, sociologists, anthropologists, biologists, neuroscientists, and medical researchers all
conduct research that is relevant to understanding aspects of human development. Consider cognitive
development. Children’s performance on cognitive measures, such as problem-solving, are influenced by
their physical health and nutrition (Anjos et al., 2013; Biddle et al., 2019), interactions with peers (Holmes
et al., 2016), and neurological development (Stiles et al., 2015), findings from the fields of medicine,
psychology, and neuroscience, respectively. To understand how people develop at all periods in life,
developmental scientists must combine insights from all of these disciplines.
Thinking in Context: Lifespan Development
1. Describe your own development. Provide personal examples that illustrate the multidimensional
nature of your own development. In what ways has your development illustrated multidirectionality?
Plasticity?
2. Consider the societal and cultural events that your parents may have experienced in their youth.
What technology was available? What historical events did they experience? What were the popular
fads of their youth? What influence do you think these sociohistorical factors may have had on your
parents’ development? Compare their sociohistorical context with the one in which you were raised.
What historical and societal events may have influenced you? What events have shaped your
generation?
3. Consider your own experiences with culture. With which culture or subculture do you identify?
How much of a role do you think your cultural membership has had in your own development? Why
might some people say that the United States has no culture? What do you think?
BASIC ISSUES IN LIFESPAN HUMAN DEVELOPMENT
LEARNING OBJECTIVE
1.2 Explain three basic issues in developmental science.
Developmental scientists agree that people change throughout life and show increases in some
capacities and decreases in others, from conception to death. Yet they sometimes disagree about how
development proceeds and what causes developmental changes. Developmental scientists’ explanations
of how people grow and change over their lives are influenced by their perspectives on three basic
issues, or fundamental questions, about human development:
1. Do people change gradually, often imperceptibly, over time, or is developmental change sudden
and dramatic?
2. What role do people play in their own development—how much are they influenced by their
surroundings, and how much do they influence their surroundings?
3. To what extent is development a function of inborn genetic characteristics, and to what extent is it
affected by the environment in which individuals live?
The following sections examine each of these questions.
Development Is Characterized by Continuous and Discontinuous Change
Do children slowly grow into adults, steadily gaining more knowledge and experience and becoming
better at reasoning? Or do they grow in spurts, showing sudden, large gains in knowledge and
reasoning capacities? Some aspects of development unfold slowly and gradually over time,
demonstrating continuous change. Children slowly gain experience and learn strategies to become
quicker at problem-solving (Siegler, 2016). Similarly, middle-aged adults experience gradual losses of
muscle and strength (Keller & Engelhardt, 2013). Other aspects of development are best described as
discontinuous change, characterized by abrupt change with individuals of various ages dramatically
different from one another. Puberty transforms children’s bodies into more adult-like adolescent bodies
(Wolf & Long, 2016), infants’ understanding and capacity for language is qualitatively different from that
of school-aged children (Rudman & Titjen, 2018), and children make leaps in their reasoning abilities
over the course of childhood, such as from believing that robotic dogs and other inanimate objects are
alive to understanding that life is a biological process (Beran et al., 2011; Zaitchik et al., 2014). As shown
in Figure 1.2, a discontinuous view of development emphasizes sudden transformation, whereas a
continuous view emphasizes gradual and steady changes.
Description
Figure 1.2 Continuous and Discontinuous Development
Source: Adapted from End of the Game (2014). “Child Development 101 –
History and Theory,” https://endofthegame.net/2014/04/15/childdevelopment-101-history-and-theory/3/.
It was once believed that development was either continuous or discontinuous—but not both. Today,
developmental scientists agree that development includes both continuity and discontinuity (Lerner et
al., 2014). Whether a particular developmental change appears continuous or discontinuous depends in
part on our point of view. Consider physical growth. We often think of increases in height as involving a
slow and steady process; each month, an infant is taller than the prior month, illustrating continuous
change. However, as shown in Figure 1.3, when researchers measured infants’ height every day, they
discovered that infants have growth days and nongrowth days, days in which they show rapid change in
height interspersed with days in which there is no change in height, illustrating discontinuous change
(Lampl et al., 2001). In this example, monthly measurements of infant height suggest gradual increases,
but daily measurements show spurts of growth, each lasting 24 hours or less. Thus, whether a given
phenomenon, such as height, is described as continuous or discontinuous can vary depending on
perspective. Most developmental scientists agree that some aspects of development are best described
as continuous and others as discontinuous (Miller, 2016).
Description
Figure 1.3 Infant Growth: A Continuous or Discontinuous Process
Source: Lampl et al. (1992).
Individuals Are Active in Development
Do people have a role in influencing how they change over their lifetimes? That is, are people active in
influencing their own development? Taking an active role means that they interact with and influence
the world around them, create experiences that lead to developmental change, and thereby influence
how they themselves change over the lifespan. Alternatively, if individuals take a passive role in their
development, they are shaped by, but do not influence, the world around them.
The prevailing view among developmental scientists is that people are active contributors to their own
development (Lerner et al., 2014; Overton, 2015). People are influenced by the physical and social
contexts in which they live, but they also play a role in influencing their development by interacting with,
and changing, those contexts (Elder et al., 2016). Even infants influence the world around them and
construct their own development through their interactions. Baby Joey smiles at each adult he passes by
as his mother pushes his stroller in the park. Adults often respond with smiles, use “baby talk,” and make
faces. Baby Joey’s actions, even simple smiles, influence adults, bringing them into close contact, making
one-on-one interactions, and creating opportunities for learning. By engaging the world around them,
thinking, being curious, and interacting with people, objects, and their environment, infants and children
are “manufacturers of their own development” (Flavell, 1992, p. 998). That is, they play an active role in
influencing their own development.
It's easy to see how this baby can influence the world around her and
construct her own development through her interactions. By smiling at each
adult she sees, she influences her world because adults are likely to smile, use
“baby talk,” and play with her in response.
iStock/monkeybusinessimages
Nature and Nurture Influence Development
Perhaps the oldest question about development concerns its origin. Referred to as the nature–nurture
debate, researchers once asked whether development is caused by nature (genetics) or nurture
(environment). Explanations that rely on nature point to inborn genetic traits and maturational processes
as causes of developmental change. Most infants take their first steps at roughly the same age,
suggesting a maturational trend that supports the role of nature in development (Payne & Isaacs, 2020).
An alternative explanation for developmental change emphasizes nurture, the environment. From this
perspective, although most begin to walk at about the same age, environmental conditions can speed
up or slow down the process. Infants who experience malnutrition may walk later than well-nourished
infants, and those who are given practice making stepping or jumping movements may walk earlier
(Siekerman et al., 2015; Worobey, 2014). Individuals are molded by the physical and social environment
in which they are raised. Many infants may walk at about the same age because they experience similar
environmental circumstances and parenting practices.
Today, developmental scientists generally agree that the nature–nurture debate is, in fact, not a debate.
Instead, most now agree that
nature and nurture are important contributors to development and
the question has changed to how do genetics and environment work together to influence child
development (Rutter, 2014; Sasaki & Kim, 2017). Thus, walking is heavily influenced by maturation
(nature), but experiences and environmental conditions can speed up or slow down the process
(nurture). Today, developmental scientists attempt to determine
nature and nurture interact and
work together to influence how people grow and change throughout life (Bjorklund, 2018a; Lickliter &
Witherington, 2017).
both
how
Thinking in Context: Lifespan Development
1. Identify ways in which you have changed very gradually over the years. Are there times in which you
showed abrupt change, such as in physical growth, strength and coordination, thinking abilities, or
social skills? In other words, in what ways is your development characterized by continuity?
Discontinuity?
2. What role did your physical and social environment play in your growth?
3. Identify examples of how a child might play an active role in his or her development. How do
children influence the world around them?
Thinking in Context: Biological Influences
1. How are nature and nurture reflected in your own development? What traits, abilities, or behaviors
do you believe are influenced by inborn factors? What role did the physical and social environment
play in your development?
2. Consider similarities and differences among family members. How might they reflect the interaction
of nature and nurture?
THEORETICAL PERSPECTIVES ON HUMAN DEVELOPMENT
LEARNING OBJECTIVE
1.3 Summarize five theoretical perspectives on human development.
Over the past century, scientists have learned much about how individuals progress, from infants to
children, to adolescents, and to adults, as well as how they change throughout adulthood.
Developmental scientists explain their observations by constructing theories of human development. A
theory is a way of organizing a set of observations or facts into a comprehensive explanation of how
something works. Theories are important tools for compiling and interpreting the growing body of
research in human development as well as determining gaps in our knowledge and making predictions
about what is not yet known.
Effective theories generate specific hypotheses, or proposed explanations for a given phenomenon, that
can be tested by research. It is important to note that this testing seeks to find flaws in the hypothesis—
not to “prove” that it is flawless. A good theory is one that is
, or capable of generating
hypotheses that can be tested and, potentially, refuted. As scientists conduct research and learn more
about a topic, they modify their theories. Updated theories often give rise to new questions and new
research studies, whose findings may further modify theories.
falsifiable
The great body of research findings in the field of lifespan human development has been organized into
several theoretical perspectives to account for the developmental changes that occur over the lifespan.
Psychoanalytic Theories
Are there powerful forces within us that make us behave as we do? Are we pushed by inner drives?
Psychoanalytic theories describe development and behavior as a result of the interplay of inner drives,
memories, and conflicts we are unaware of and cannot control. These inner forces influence our
behavior throughout our lives. Freud and Erikson are two key psychoanalytic theorists.
Freud’s Psychosexual Theory
Sigmund Freud (1856–1939), a Viennese physician, is credited as the father of the psychoanalytic
perspective. Freud believed that much of our behavior is driven by unconscious impulses that are
outside of our awareness. He described development as the progression through a series of
, periods in which unconscious drives are focused on different parts of the body,
making stimulation to those parts a source of pleasure. Freud explained that the task for parents is to
strike a balance between overgratifying and undergratifying a child’s desires at each stage to help the
child develop a healthy personality with the capacity for mature relationships throughout life. Notably,
Freud did not study children; his theory grew from his work with female psychotherapy patients (Crain,
2016).
psychosexual stages
Many of Freud’s ideas, such as the notion of unconscious processes of which we are unaware, have
permeated popular culture. Notably, Freud’s theory was the first to emphasize the importance of early
family experience and especially the parent–child relationship for development (Bargh, 2013). However,
the psychosexual stage framework’s emphasis on childhood sexuality, especially the phallic stage, is
unpopular and not widely accepted (Westen, 1998). In addition, unconscious drives and other
psychosexual constructs are not falsifiable. They are not supported by research because they cannot be
directly observed and tested (Miller, 2016). How are we to study unconscious drives, for instance, when
we are not aware of them?
Sigmund Freud (1856–1939), the father of the psychoanalytic perspective,
believed that much of our behavior is driven by unconscious impulses.
Library of Congress
Erikson’s Psychosocial Theory
Erik Erikson (1902–1994) was influenced by Freud, but he placed less emphasis on unconscious
motivators of development and instead focused on the role of the social world, society, and culture
(Table 1.2). According to Erikson, throughout their lives, individuals progress through eight
that include changes in how they understand and interact with others, as well as changes in how
they understand themselves and their roles as members of society (Erikson, 1950). Each stage presents a
unique developmental task, which Erikson referred to as a crisis or conflict that must be resolved. How
well individuals address the crisis determines their ability to deal with the demands made by the next
stage of development. Children’s success in achieving a sense of trust in others influences their progress
in developing a sense of autonomy, the ability to be independent and guide their own behavior.
stages
psychosocial
Regardless of their success in resolving a crisis of a given stage, individuals are driven by biological
maturation and social expectations to the next psychosocial stage. No crisis is ever fully resolved, and
unresolved crises are revisited throughout life. Although Erikson believed that it is never too late to
resolve a crisis, resolving a crisis from a previous stage may become more challenging over time as
people focus on current demands and the crises of their current psychosocial stages.
Erik Erikson (1902–1994) posited that, throughout their lives, people progress
through eight stages of psychosocial development.
Jon Erikson/Science Source
As one of the first lifespan views of development, Erikson’s psychosocial theory sees development as
spanning well beyond childhood. Erikson’s theory offers a positive view of development and includes the
role of society and culture, largely ignored by Freud. In addition, Erikson based his theory on a broad
range of cases, including larger and more diverse samples of people than did Freud. Largely viewed as
unfalsifiable, Erikson’s theory is criticized as difficult to test. Yet it has nonetheless sparked research on
specific stages, most notably on the development of identity during adolescence and the drive to guide
youth and contribute to the next generation during middle adulthood (Crain, 2016). Erikson’s lifespan
theory of development holds implications for every period of life. We will revisit his theory throughout
this book.
Table 1.2 Psychoanalytic Theories of Development
Approximate
Freud’s Psychosexual Theory
Age
Erikson’s Psychosocial
Theory
Approximate Freud’s Psychosexual Theory
Age
0 to 18
Oral
Basic drives focus on the mouth, tongue, and
months
gums. Feeding and weaning influence
personality development. Freud believed that
failure to meet oral needs influences adult
habits centering on the mouth, such as
fingernail biting, overeating, smoking, or
excessive drinking.
Erikson’s Psychosocial
Theory
Trust vs.
Infants learn to
Mistrust
trust that
others will
fulfill their
basic needs
(nourishment,
warmth,
comfort) or to
lack
confidence
that their
needs will be
met.
18 months to Anal
Basic drives are oriented toward the anus, and Autonomy Toddlers learn
3 years
toilet training is an important influence on
vs. Shame
to be selfpersonality development. If caregivers are too and Doubt sufficient and
demanding, pushing the child before he or she
independent
is ready, or if caregivers are too lax, individuals
through toilet
may develop issues of control such as a need
training,
to impose extreme order and cleanliness on
feeding,
their environment or extreme messiness and
walking,
disorder.
talking, and
exploring or to
lack
confidence in
their own
abilities and
doubt
themselves.
3 to 6 years
Phallic In Freud’s most controversial stage, basic
Initiative vs. Young children
drives shift to the genitals. The child develops
Guilt
become
a romantic desire for the opposite-sex parent
inquisitive,
and a sense of hostility and/or fear of the
ambitious, and
same-sex parent. The conflict between the
eager for
child’s desires and fears arouses anxiety and
responsibility
discomfort. It is resolved by pushing the
or experience
desires into the unconscious and spending
overwhelming
time with the same-sex parent and adopting
guilt for their
his or her behaviors and roles, adopting
curiosity and
societal expectations and values. Failure to
overstepping
resolve this conflict may result in guilt and a
boundaries.
lack of conscience.
6 years to
Latency This is not a stage but a time of calm between Industry vs. Children learn
puberty
stages when the child develops talents and
Inferiority
to be
skills and focuses on school, sports, and
hardworking,
friendships.
competent,
and productive
by mastering
new skills in
school,
friendships,
and home life
or experience
difficulty,
leading to
feelings of
inadequacy
and
incompetence.
Approximate Freud’s Psychosexual Theory
Age
Adolescence Genital With the physical changes of early
adolescence, the basic drives again become
oriented toward the genitals. The person
becomes concerned with developing mature
adult sexual interests and sexual satisfaction in
adult relationships throughout life.
Early
adulthood
Middle
adulthood
Erikson’s Psychosocial
Theory
Identity vs. Adolescents
Role
search for a
Confusion
sense of self by
experimenting
with roles.
They also look
for answers to
the question,
“Who am I?” in
terms of career,
sexual, and
political roles
or remain
confused
about who
they are and
their place in
the world.
Intimacy vs. Young adults
Isolation
seek
companionship
and a close
relationship
with another
person or
experience
isolation and
self-absorption
through
difficulty
developing
intimate
relationships
and sharing
with others.
Generativity Adults
vs.
contribute to,
Stagnation establish, and
guide the next
generation
through work,
creative
activities, and
parenting or
stagnate,
remaining
emotionally
impoverished
and concerned
about
themselves.
Approximate Freud’s Psychosexual Theory
Age
Late
adulthood
Erikson’s Psychosocial
Theory
Integrity vs. Older adults
Despair
look back at
life to make
sense of it,
accept
mistakes, and
view life as
meaningful
and productive
or feel despair
over goals
never reached
and fear of
death.
Behaviorist and Social Learning Theories
In response to psychoanalytic theorists’ emphasis on the unconscious as an invisible influence on
development and behavior, some scientists pointed to the importance of studying observable behavior
rather than thoughts and emotion, which cannot be seen or objectively verified. Theorists who study
behaviorism examine only behavior that can be observed and believe that all behavior is influenced by
the physical and social environment. Consider this famous quote from John Watson (1925), a founder of
behaviorism:
Give me a dozen healthy infants, well formed, and my own specified world to bring them up in
and I’ll guarantee to take any one at random and train him to become any type of specialist I
might select—doctor, lawyer, artist, merchant, chief, and yes, even beggar-man and thief,
regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors.
(p. 82)
By controlling an infant’s physical and social environment, Watson believed he could control the child’s
destiny. Behaviorist theory is also known as
because it emphasizes how people and
animals learn new behaviors as a function of their environment. As discussed in the following sections,
classical and operant conditioning are two forms of behaviorist learning; social learning integrates
elements of behaviorist theory and information processing theories.
learning theory
Classical Conditioning
Classical conditioning is a form of learning in which a person or animal comes to associate
environmental stimuli with physiological responses. Ivan Pavlov (1849–1936), a Russian physiologist,
discovered the principles of classical conditioning when he noticed that dogs naturally salivate when
they taste food, but they also salivate in response to various sights and sounds that occur before they
taste food, such as their bowl clattering or their owner opening the food cupboard. Pavlov tested his
observation by pairing the sound of a tone with the dog’s food; the dogs heard the tone, then received
their food. Soon the tone itself began to elicit the dogs’ salivation.
Ivan Pavlov (1849–1936) discovered classical conditioning when he noticed
that dogs naturally salivate when they taste food, but they also salivate in
response to various sights and sounds that they associate with food.
Sovfoto/Universal Images Group/Newscom
Through classical conditioning, a neutral stimulus (in this example, the sound of the tone) comes to elicit
a response originally produced by another stimulus (food). Newborn infants can demonstrate classical
conditioning when a neutral stimulus (such as stroking the forehead) is paired with an unconditioned
stimulus (sugar water, which makes the infant suck vigorously, an unconditioned response) (Figure 1.4).
Soon, stroking the newborn’s forehead yields the sucking behaviors, indicating that sucking is a
conditioned response. Many fears, as well as other emotional associations, are the result of classical
conditioning. Some children may fear a trip to the doctor’s office because they associate the doctor’s
office with the discomfort they felt upon receiving a vaccination shot. Classical conditioning applies to
physiological and emotional responses only, yet it is a cornerstone of psychological theory. A second
behaviorist theory accounts for voluntary, non-physiological responses, as described in the following
section.
Description
Figure 1.4 Classical Conditioning in a Newborn
Operant Conditioning
Perhaps it is human nature to notice that the consequences of our behavior influence our future
behavior. A teenager who arrives home after curfew and is greeted with a severe scolding may be less
likely to return home late in the future. A child who is praised for setting the dinner table may be more
likely to spontaneously set the table in the future. These two examples illustrate the basic tenet of B. F.
Skinner’s (1905–1990) theory of operant conditioning, which holds that behavior becomes more or less
probable depending on its consequences. According to Skinner, a behavior followed by a rewarding or
pleasant outcome, called reinforcement, will be more likely to recur, but one followed by an aversive or
unpleasant outcome, called punishment, will be less likely to recur.
Operant conditioning explains much about human behavior, including how we learn skills and habits.
Behaviorist ideas about operant conditioning and the nature of human behavior are woven into the
fabric of North American culture and are often applied to understand parenting and parent–child
interactions (Troutman, 2015). Developmental scientists tend to disagree with operant conditioning’s
emphasis on external events (reinforcing and punishing consequences) over internal events (thoughts
and emotions) as influences on behavior (Crain, 2016). That is, controlling people’s environments can
influence their development, but change can also occur from within, through people’s own thoughts and
actions. Children, adolescents, and adults can devise new ideas and learn independently, without
experiencing reinforcement or punishment. This is consistent with the lifespan concept that individuals
are active contributors to their development.
Social Learning Theory
Like behaviorists, Albert Bandura (1925–2021) believed that the physical and social environments are
important, but he also advocated for the role of thought and emotion as contributors to development.
According to Bandura’s social learning theory, people actively process information—they think and they
feel emotion—and their thoughts and feelings influence their behavior. The physical and social
environment influences our behavior through its effect on our thoughts and emotions. The teenager
who breaks his curfew and is met by upset parents may experience remorse, which may then make him
less likely to come home late in the future. In this example, the social environment (a discussion with
upset parents) influenced the teen’s thoughts and emotions (feeling bad for upsetting his parents),
which then influenced the teen’s behavior (not breaking curfew in the future). In other words, our
thoughts and emotions about the consequences of our behavior influence our future behavior. We do
not need to experience punishment or reinforcement to change our behavior (Bandura, 2012). We can
learn by thinking about the potential consequences of our actions.
One of Bandura’s most enduring ideas about development is that people learn through observing and
imitating others, which he referred to as observational learning (Bandura, 2010). This finding suggests
that children who observe violence rewarded, such as a child grabbing (and successfully obtaining)
another child’s toy, may imitate what they see and use aggressive means to take other children’s toys.
People also learn by observing the consequences of others’ actions. A child observer might be less likely
to imitate a child who takes another child’s toy if the aggressor is scolded by a teacher and placed in
time out. Observational learning is one of the most powerful ways in which we learn.
In a classic study conducted by Albert Bandura, children who observed an
adult playing with a bobo doll toy roughly imitated those behaviors,
suggesting that children learn through observation.
Mirrorpix/Contributor/Getty Images
Bandura has also contributed to the field of lifespan human development through the concept of
reciprocal determinism, according to which individuals and the environment interact and influence each
other (Bandura, 2011, 2018). In contrast with behaviorist theorists, Bandura viewed individuals as active
in their development rather than passively molded by their physical and social environments.
Specifically, development is a result of interactions between the individual's characteristics, his or her
behavior, and the physical and social environment (Figure 1.5).
Description
Figure 1.5 Bandura’s Model of Reciprocal Determinism
People’s characteristics influence their behavior and the environments they seek. Suppose Issac is
inquisitive and assertive, which makes him quick to challenge others in debate. This behavior
(challenging others to debate), in turn, stimulates those around him to participate in debate. But
suppose, too, that Issac’s behavior (being quick to debate) does not result only from his personal
characteristics (inquisitiveness and assertiveness). It is also influenced by the environment (e.g., being
surrounded by smart people who enjoy debating). Issac’s behavior also influences the environment (e.g.,
people who enjoy debating are more likely to engage Issac, while people who avoid debating are less
likely to engage him). This is an example of the complex interplay among person, behavior, and physical
and social environment that underlies much of what we will discuss throughout this book.
Behaviorist theories have made important contributions to understanding lifespan human development.
Concepts such as observational learning, reinforcement, and punishment are powerful means of
explaining human behavior and hold implications for parents, teachers, and anyone who works with
people of any age. Social learning theory and reciprocal determinism illustrate the role that individuals
have in their own development, a more complex explanation for development and behavior. We will
revisit these concepts in later chapters.
Cognitive Theories
Cognitive theorists view cognition—thought—as essential to understanding people’s functioning across
the lifespan. In this section, we look at some of the ideas offered by cognitive–developmental theory and
information processing theory.
Piaget’s Cognitive–Developmental Theory
Swiss scholar Jean Piaget (1896–1980) was the first scientist to systematically examine infants’ and
children’s thinking and reasoning. Piaget believed that to understand children, we must understand how
they think, because thinking influences all behavior. Piaget’s cognitive–developmental theory views
children and adults as active explorers of their world, driven to learn by interacting with the world
around them and organizing what they learn into cognitive schemas, or concepts, ideas, and ways of
interacting with the world. Through these interactions, they construct and refine their own cognitive
schemas, thereby contributing to their own cognitive development.
Jean Piaget (1896–1980) believed that children’s drive to explore and
understand the world around them propels them through four stages of
cognitive development.
Bill Anderson/Science Source
Piaget proposed that children’s drive to explore and understand the world—to construct more
sophisticated cognitive schemas—propels them through four stages of cognitive development, as
shown in Table 1.3.
Table 1.3 Piaget’s Stages of Cognitive Development
Approximate
Age
Sensorimotor Birth to 2
years
Preoperations 2 to 6 years
Stage
Concrete
operations
7 to 11 years
Formal
operations
12 years to
adulthood
Description
Infants understand the world and think using only their senses and
motor skills, by watching, listening, touching, and tasting.
Preschoolers explore the world using their own thoughts as guides and
develop the language skills to communicate their thoughts to others.
Despite these advances, their thinking is characterized by several errors
in logic.
School-aged children become able to solve everyday logical problems.
Their thinking is not yet fully mature because they are able to apply
their thinking only to problems that are tangible and tied to specific
substances.
Adolescents and adults can reason logically and abstractly about
possibilities, imagined instances and events, and hypothetical concepts.
Piaget’s cognitive–developmental theory transformed the field of developmental psychology and
remains one of the most widely cited developmental theories. It was the first to consider
infants
and children think and to view people as active contributors to their development. In addition, Piaget’s
concept of cognitive stages and the suggestion that children’s reasoning is limited by their stage has
implications for education—specifically, the idea that effective instruction must match the child’s
developmental level.
how
Some critics of cognitive–developmental theory argue that Piaget focused too heavily on cognition and
ignored emotional and social factors in development (Crain, 2016). Others believe that Piaget neglected
the influence of contextual factors by assuming that cognitive–developmental stages are universal—that
all individuals everywhere progress through the stages in a sequence that does not vary. Some cognitive
theorists argue that cognitive development is not a discontinuous, stage-like process but instead is a
continuous process (Birney & Sternberg, 2011), as described in the following section.
Information Processing Theory
A developmental scientist presents a 5-year-old child with a puzzle in which a dog, cat, and mouse must
find their way to a bone, piece of fish, and hunk of cheese. To solve the puzzle, the child must move all
three animals to the appropriate locations. How will the child approach this task? Which item will she
move first? What steps will she take? What factors influence whether and how quickly a child completes
this task? Finally, how does the 5-year-old child’s process and performance differ from that of children
older and younger than herself?
The problem described above illustrates the questions studied by developmental scientists who favor
information processing theory, which posits that the mind works in ways similar to a computer in that
information enters and then is manipulated, stored, recalled, and used to solve problems (Halford &
Andrews, 2011). Unlike the theories we have discussed thus far, information processing theory is not one
theory that is attributed to an individual theorist. Instead, there are many information processing
theories, and each emphasizes a different aspect of thinking (Callaghan & Corbit, 2015; Müller et al.,
2015; Ristic & Enns, 2015). Some theories focus on how people perceive, focus on, and take in
information. Others examine how people store information, create memories, and remember
information. Still others examine problem-solving—how people approach and solve problems in school,
the workplace, and everyday life.
According to information processing theorists, we are born with the ability to process information. Our
mental processes of noticing, taking in, manipulating, storing, and retrieving information do not show
the radical changes associated with stage theories. Instead, development is continuous and entails
changes in the efficiency and speed of thought. Maturation of the brain and nervous system contributes
to changes in our information processing abilities. We tend to become more efficient at attending to,
storing, and processing information over the childhood years and to slow over the adult years (Luna et
al., 2015). Experience and interaction with others also contribute by helping us learn new ways of
managing and manipulating information. We naturally engage in information processing throughout our
lives. We will discuss these changes and their implications for children, adolescents, and adults in later
chapters.
Information processing theory offers a complex and detailed view of how we think, which permits
scientists to make specific predictions about behavior and performance that can be tested in research
studies. Indeed, information processing theory has generated a great many research studies and has
garnered much empirical support (Halford & Andrews, 2011). Critics of the information processing
perspective argue that a computer model cannot capture the complexity of the human mind and
people’s unique cognitive abilities. In addition, findings from laboratory research may not extend to
everyday contexts in which people must adapt to changing circumstances and challenges to attention
(Miller, 2016).
Contextual Theories
Contextual theories emphasize the role of the sociocultural context in development. People of all ages
are immersed in a system of social contexts that interact. They are inseparable from the cultural beliefs
and societal, neighborhood, and familial contexts in which they live. Several contextual theorists describe
development as a function of interactions between individuals and the contextual systems in which they
are embedded.
Vygotsky’s Sociocultural Theory
Writing at the same time as Piaget, Russian scholar Lev Vygotsky (1896–1934) offered a different
perspective on development, especially cognitive development, that emphasized the importance of
culture. Recall that culture refers to the beliefs, values, customs, and skills of a group; it is a product of
people’s interactions in everyday settings (Markus & Kitayama, 2010). Vygotsky’s (1978) sociocultural
theory examines how culture is transmitted from one generation to the next through social interaction.
Children interact with adults and more experienced peers as they talk, play, and work alongside them. It
is through these formal and informal social contacts that children learn about their culture and what it
means to belong to it. By participating in cooperative dialogues and receiving guidance from adults and
more-expert peers, children adopt their culture’s perspectives and practices, learning to think and
behave as members of their society (Rogoff, 2016). Over time, they become able to apply these ways of
thinking to guide their own actions, thus requiring less assistance from adults and peers (Rogoff et al.,
2014).
Vygotsky's sociocultural theory holds important implications for understanding cognitive development.
Like Piaget, Vygotsky emphasized that children actively participate in their development by engaging
with the world around them. However, Vygotsky also viewed cognitive development as a social process
that relies on interactions with adults, more-mature peers, and other members of their culture. Vygotsky
also argued that acquiring language is a particularly important milestone for children because it enables
them to think in new ways and have more sophisticated dialogues with others, advancing their learning
about culturally valued perspectives and activities. We will revisit Vygotsky’s ideas about the roles of
culture, language, and thought in Chapter 7.
Vygotsky’s sociocultural theory is an important addition to the field of lifespan human development
because it is the first theory to emphasize the role of the cultural context in influencing people’s
development. Critics argue that sociocultural theory overemphasizes the role of context, minimizes the
role of individuals in their own development, and neglects the influence of genetic and biological factors
(Crain, 2016). Another perspective on cognitive development, described next, refocuses attention on the
individual.
Lev Vygotsky (1896–1934) emphasized the importance of culture in
development. Children actively engage their social world, and the social
world shapes development by transmitting culturally relevant ways of
thinking and acting that guide children’s thought and behavior.
Heritage Image Partnership Ltd/Alamy Stock Photo
Bronfenbrenner’s Bioecological Systems Theory
Similar to Vygotsky, Urie Bronfenbrenner (1917–2005) believed that individuals are active in their own
development. Specifically, Bronfenbrenner’s bioecological systems theory poses that development is a
result of the ongoing interactions among biological, cognitive, and socioemotional changes within
individuals and their changing contexts (Figure 1.6) (Bronfenbrenner & Morris, 2006). Bronfenbrenner
proposed that all individuals are embedded in, or surrounded by, a series of contexts: home, school,
neighborhood, culture and society. Contexts are organized into a series of systems in which individuals
are embedded and that interact with one another and the person to influence development.
Description
Figure 1.6 Bronfenbrenner’s Bioecological Systems Theory
Source: Adapted from Bronfenbrenner & Morris (2006).
At the center of the bioecological model is the individual. Ontogenetic development refers to the
changes that take place within the individual. Ontogenetic development comprises the developing
person’s interacting biological, cognitive, and socioemotional traits The developing person’s genetic,
psychological, socioemotional, and personality traits interact and influence each other. Physical
development, such as brain maturation, may influence children’s cognitive development, such as
reasoning and the ability to consider other people’s perspectives, which in turn may influence social
development, the ability to have more complex and intimate friendships. In turn, social development
may influence cognitive development, as children learn from each other. In this way the various forms of
development interact. Ontogenetic development is influenced by, but also influences, the many contexts
in which we are embedded (Bronfenbrenner & Morris, 2006).
Perhaps the most visible context is the microsystem, the innermost level of the bioecological system,
which includes interactions with the immediate physical and social environment surrounding the person,
such as family, peers, school, and work. Because the microsystem contains the developing person, it has
an immediate and direct influence on his or her development. Peer relationships can influence a
person’s sense of self-esteem, social skills, and emotional development.
Microsystems naturally interact. Experiences in the home (one microsystem) influence those at school
(another microsystem). Parents who encourage and provide support for reading will influence the child’s
experiences in the classroom. These interactions comprise the mesosystem, which refers to the relations
among microsystems or connections among contexts, such as home, peer group, school, work, and
neighborhood. Like the microsystem, the mesosystem has a direct influence on the individual because
he or she is a participant in it.
The exosystem consists of settings in which the individual is not a participant but that nevertheless
influence him or her. A child typically does not participate in a parent’s workplace, yet the work setting
has an indirect influence on the child because it affects the parent’s mood. The availability of funding for
schools, another exosystem factor, indirectly affects children by influencing the availability of classroom
resources. The exosystem is an important contribution to our understanding of development because it
shows us how the effects of outside factors trickle down and indirectly affect individuals.
The macrosystem is the greater sociocultural context in which the microsystem, mesosystem, and
exosystem are embedded. It includes cultural values, legal and political practices, and other elements of
the society at large. The macrosystem indirectly influences the child because it affects each of the other
contextual levels. Cultural beliefs about the value of education (macrosystem) influence funding
decisions made at national and local levels (exosystem), as well as what happens in the classroom and in
the home (mesosystem and microsystem).
By its very nature, the bioecological model is always shifting because individuals and their contexts
interact dynamically and perpetually, resulting in a constant state of change. The final element of the
bioecological system is the chronosystem, which refers to the element of time. The bioecological system
changes over time and the time in which we live influences our development. Large-scale social
changes, such as those that accompany war, natural disasters, and epidemics, can influence each level of
the bioecological system. Neighborhood resources may change over time with changes in local policies
and funding. Our relationships with parents, friends, and teachers change over time. As people grow and
change, they take on and let go of various roles. Graduating from college, getting married, and
becoming a parent involve changes in roles and shifts in microsystems. These shifts in contexts, called
, occur throughout life.
ecological transitions
Recently, the bioecological model has been criticized for its vague explanation of development,
especially the role of culture (Vélez-Agosto et al., 2017). Situated in the macrosystem, culture is said to
influence development through the interdependence of the systems. Yet current conceptualizations of
culture view it as all the processes used by people as they make meaning or think through interactions
with group members (Mistry et al., 2016; Yoshikawa et al., 2016). Critics therefore argue that since culture
is manifested in our daily activities, it is inherent in each bioecological level (Vélez-Agosto et al., 2017).
Moreover, cultural changes derive from interactions and pressures at each ecological level, not simply
the macrosystem as Bronfenbrenner believed (Varnum & Grossmann, 2017).
A second criticism arises from the sheer complexity of the bioecological model and its attention to
patterns and dynamic interactions. We can never measure and account for all of the potential individual
and contextual influences on development at once, making it difficult to devise research studies to test
the validity of the model. Proponents argue that it is not necessary to test all of the model’s components
at once. Instead, smaller studies can examine each component over time (Jaeger, 2016; Tudge et al.,
2016). In any case, bioecological theory remains an important contribution toward explaining
developmental change across the lifespan and is a theory that we will consider throughout this book.
Dynamic Systems Theory
Some of the major concepts that we have discussed throughout this chapter include the interaction of
genetics and environment and the active role of children in their own development. Children are
motivated to understand their experiences and control their environment. Each child’s characteristics
and environmental circumstances and interactions are unique and influence how they approach
developmental tasks and problems, resulting in unique patterns of functioning. According to Esther
Thelen’s dynamic systems theory, children’s developmental domains, maturation, and environment form
an integrated system that is constantly changing, resulting in developmental change and the emergence
of new abilities (Thelen, 1995, 2000).
Many childhood milestones, such as an infant’s first steps or first word, might look like isolated
achievements, but they actually develop systematically and are the result of skill-building, with each new
skill (such as pulling up to stand or babbling sounds) preparing an infant to tackle the next (Thelen,
1995, 2000). Simple actions and abilities are combined to provide more complex and effective ways for
babies to explore and engage the world. An infant might combine the distinct abilities to sit upright,
hold the head upright, match motor movements to vision, reach out an arm, and grasp to coordinate
reaching movements to obtain a desired object (Corbetta & Snapp-Childs, 2009; Spencer et al., 2000).
Development reflects goal-oriented behavior because it is initiated by the infant or child’s desire to
accomplish something, such as picking up a toy or expressing themself. Infants’ abilities and their
immediate environments, including environmental supports and constraints, determine whether and
how the goal can be achieved (Spencer et al., 2000). Although Thelen described developmental systems
theory with motor development in mind, theorists are now applying it to understand children’s cognitive
and emotional development as well as mental health (Guo et al., 2017; Mascolo et al., 2016).
Ethology and Evolutionary Developmental Theory
What motivates parents of most species to care for their young? Some researchers argue that caregiving
behaviors have an evolutionary basis. Ethology is the scientific study of the evolutionary basis of
behavior (Bateson, 2015). In 1859, Charles Darwin proposed his theory of evolution, explaining that all
species adapt and evolve over time. Specifically, traits that enable a species to adapt, thrive, and mate
tend to be passed to succeeding generations because they improve the likelihood of the individual's and
species’ survival. Several early theorists applied the concepts of evolution to behavior. Konrad Lorenz
and Kiko Tinbergen, two European zoologists, observed animal species in their natural environments and
noticed patterns of behavior that appeared to be inborn, emerged early in life, and ensured the animals’
survival. Shortly after birth, goslings imprint to their mothers, meaning that they bond to her and follow
her. Imprinting aids the goslings’ survival because it ensures that they stay close to their mother, get fed,
and remain protected. In order for imprinting to occur, the mother goose must be present immediately
after the goslings hatch; mothers instinctively stay close to the nest so that their young can imprint
(Lorenz, 1952).
According to John Bowlby (1969), humans also display biologically preprogrammed behaviors that have
survival value and promote development. Caregivers naturally respond to infants’ cues. Crying, smiling,
and grasping are inborn ways that infants get attention from caregivers, bring caregivers into physical
contact, and ensure that they will be safe and cared for. Such behaviors have adaptive significance
because they meet infants’ needs and promote the formation of bonds with caregivers, ensuring that the
caregivers will feel a strong desire and obligation to care for them (Bowlby, 1973). In this way, innate
biological drives and behaviors work together with experience to influence adaptation and ultimately an
individual’s survival.
Another theory, evolutionary developmental theory, applies principles of evolution and scientific
knowledge about the interactive influence of genetic and environmental mechanisms to understand the
changes people undergo throughout their lives (Bjorklund, 2018b; Witherington & Lickliter, 2016).
Genetic factors and biological predispositions interact with the physical and social environment to
influence development, and Darwinian natural selection determines what genes and traits are passed on
to the next generation (Bjorklund, 2018b; Witherington & Lickliter, 2016).
You may have wondered whether you—your abilities, personality, and competencies—result from your
genes or from the physical and social environment in which you were raised. Evolutionary
developmental scientists explain that this is the wrong question to ask because genes and context
interact in an ever-changing way so that it is impossible to isolate the contributions of each to
development (Witherington & Lickliter, 2016). Our traits and characteristics are influenced by genes, but
contextual factors influence the expression of genetic instructions, determining whether and how genes
are shown. Gravity, light, temperature, and moisture can influence how genes are expressed and
therefore how individuals develop (Meaney, 2017). In some reptiles, such as crocodiles, sex is determined
by the temperature in which the organism develops. Eggs incubated at one range of temperatures
produce male crocodiles and at another temperature produce female crocodiles (Pezaro et al., 2017). In
this way, a contextual factor—temperature—determines how genes are expressed: sex.
Shortly after birth, goslings imprint to their mothers, meaning that they bond
to her and will follow her to ensure they will be fed and remain protected.
Ethologists propose that animal and human caregiving behaviors have an
evolutionary basis.
iStock/EmilyNorton
Evolutionary developmental theory views people as active in their development, influencing their
contexts, responding to the demands for adaptation posed by their contexts, and constantly interacting
with and adapting to the world around them. The relevance of both biological and contextual factors to
human development is indisputable, and most developmental scientists appreciate the contributions of
evolutionary developmental theory (DelGiudice, 2018; Frankenhuis & Tiokhin, 2018; Legare et al., 2018).
The ways in which biology and context interact and their influence on development change over the
course of the lifetime, as we will discuss throughout this book.
The many theories of human development offer complementary and contrasting views of how we
change throughout our lifetimes. Table 1.4 provides a comparison of theories of human development.
Table 1.4 Comparing Theories of Human Development
Are individuals active
or passive in their
development?
People are
People are driven by inborn
driven by inborn
drives, but the extent to which
instincts and are not
the drives are satisfied influences active participants in
developmental outcomes.
their development.
People are
Biological and social forces
active in their
propel people through the
development because
stages, and social and
they interact with their
psychosocial influences
social world to resolve
determine the outcome of each
psychosocial tasks.
stage.
Environmental
People are
influences shape behavior.
shaped and molded by
their environment.
Greater emphasis on nature:
Passive:
Is development
continuous or
discontinuous?
Stages
Both nature and nurture:
Active:
Discontinuous: Stages
Nurture:
Passive:
Continuous: Gradual
Is development influenced by
nature or nurture?
Freud’s
psychosexual
theory
Erikson’s
psychosocial
theory
Behaviorist
theory
Discontinuous:
process of learning
new behaviors
Are individuals active
or passive in their
development?
Inborn
Individuals are
characteristics and the physical
influenced by the
and social environment influence environment but also
behavior.
play an active role in
their development
through reciprocal
determinism.
An
Individuals
innate drive to learn coupled with actively interact with
brain development leads people the world to create
to interact with the world.
their own schemas.
Opportunities provided by the
physical and social environment
influence development.
People
People attend
are born with processing
to, process, and store
capacities that develop through
information.
maturation and environmental
influences.
People
Individuals
learn through interactions with
actively interact with
more-skilled members of their
members of their
culture; capacities are influenced culture.
by genes, brain development,
and maturation.
Is development influenced by
nature or nurture?
Bandura’s social
learning theory
Piaget’s
cognitive–
developmental
theory
Information
processing
theory
Vygotsky’s
sociocultural
theory
Both nature and nurture:
Active:
Both nature and nurture:
Active:
Discontinuous: Stages
Both nature and nurture:
Active:
Continuous: Gradual
Both nature and nurture:
Active:
Continuous:
Both nature and nurture:
Active: People interact Continuous:
Both nature and nurture:
Active:
Bronfenbrenner’s
People’s
bioecological
inborn and biological
systems theory
characteristics interact with an
ever-changing context to
influence behavior.
Dynamic systems
theory
Developmental domains,
maturation, and environment
form an integrated system.
Ethology and
evolutionary
developmental
theory
Is development
continuous or
discontinuous?
Gradual
process of learning
new behaviors
with their contexts,
being influenced by
their contexts but also
determining what
kinds of physical and
social environments
are created and how
they change.
Development
reflects goal-oriented
behavior by the desire
to accomplish goals.
Continuous:
increase of skills and
capacities
Continuous
interactions with
others lead to
developing new
reasoning capacities
and skills.
People
constantly change
through their
interactions with the
contexts in which they
are embedded.
Continuous: New
developmental
achievements are the
result of systematic
skill-building.
Both nature and nurture: Genetic Active: People interact Both continuous and
programs and biological
with their physical and discontinuous: People
predispositions interact with the social environment.
physical and social environment
to influence development, and
Darwinian natural selection
determines what genes and traits
are passed on to the next
generation.
gradually grow and
change throughout
life, but there are
sensitive periods in
which specific
experiences and
developments must
occur.
Thinking in Context: Applied Developmental Science
Just after delivering a healthy baby girl, Maria and Fernando are overwhelmed by the intense love they
feel for her. Like most new parents, they also worry about their new responsibility. They hope that their
baby will develop a strong, secure, and close bond to them. They want their baby to feel loved and to
love them.
1. What advice would a psychoanalytic theorist give Maria and Fernando? Contrast psychoanalytic
with behaviorist perspectives. How might a behaviorist theorist approach this question?
2. How might an evolutionary developmental theorist explain bonding between parents and
infants? What advice might an evolutionary developmental theorist give to Maria and Fernando?
3. Considering bioecological systems theory, what microsystem and mesosystem factors influence
the parent–child bond? What role might exosystem and macrosystem factors take?
RESEARCH IN HUMAN DEVELOPMENT
LEARNING OBJECTIVE
1.4 Describe the methods and research designs used to study human development.
The many theories of lifespan human development differ in focus and explanation, but they all result
from scientists’ attempts to organize observations of people at all ages. Developmental scientists
conduct research to gather information and answer questions about how people grow and change over
their lives. They devise theories to organize what they learn from research and to suggest new
hypotheses to test in research studies. In turn, research findings are used to modify theories. By
conducting multiple studies over time, developmental scientists refine their theories about lifespan
human development and determine new questions to ask.
The Scientific Method
Researchers employ the scientific method, a process of posing and answering questions by making
careful and systematic observations and gathering information. The scientific method provides an
organized way of formulating questions, finding answers, and communicating research discoveries. Its
basic steps are as follows:
1. Identify the research question or problem to be studied and formulate the hypothesis, or proposed
explanation, to be tested.
2. Gather information to address the research question.
3. Summarize the information gathered and determine whether the hypothesis is refuted, or shown to
be false.
4. Interpret the summarized information, consider the findings in light of prior research studies, and
share findings with the scientific community and world at large.
In practice, the scientific method usually does not proceed in such a straightforward, linear fashion.
Frequently, research studies raise as many questions as they answer—and sometimes more. Unexpected
findings can prompt new studies. Researchers may repeat an experiment (called a
) to see
whether the results are the same as previous ones. Sometimes analyses reveal flaws in data collection
methods or research design, prompting a revised study. Experts may also disagree on the interpretation
of a study. Researchers may then conduct new studies to test new hypotheses and shed more light on a
given topic. For all of these reasons, scientists often say the scientific method is “messy.”
replication
Methods of Data Collection
The basic challenge that developmental scientists face in conducting research is determining how to
measure their topic of interest. What information is important? How can it be gathered? Scientists use
the term
to refer to the information they collect. How can we gather data about children,
adolescents, and adults? Should we simply talk with our participants? Watch them as they progress
through their days? Hook them up to machines that measure physiological activity such as heart rate or
brain waves? Developmental scientists use a variety of different methods, or measures, to collect
information.
data
Observational Measures
Some researchers collect information by watching and monitoring people’s behavior. Developmental
scientists employ two types of observational measures: naturalistic observation and structured
observation.
Scientists who use naturalistic observation observe and record behavior in natural, real-world settings.
Coplan et al. (2015) studied peer interaction patterns in children by observing 9- to 12-year-old children
in the schoolyard during recess and lunch. They recorded the children’s activity and interaction with
peers and found that children who were consistently unengaged with peers tended to show high levels
of problems, such as anxiety, depression, and loneliness, as reported by both the children and their
mothers.
A challenge of using naturalistic observation is that sometimes the presence of an observer causes those
being observed to behave unnaturally. This is known as
. One way of reducing the
effect of participant reactivity is to conduct multiple observations so that the participants get used to the
observer and return to their normal behavior. Another promising method of minimizing participant
reactivity is to use an
(EAR) (Mehl, 2017). Participants carry the
EAR as they go about their daily lives. The EAR captures segments of information over time: hours, days,
or even weeks. It yields a log of people’s activities as they naturally unfold. The EAR minimizes
participant reactivity because the participant is unaware of exactly when the EAR is recording.
Researchers who study child trauma use EAR to sample conversations between parents and children to
understand how parent–child interactions influence children’s adjustment and how the family
environment can aid children’s recovery from trauma (Alisic et al., 2016).
participant reactivity
electronically activated voice recorder
Naturalistic observation permits researchers to observe patterns of behavior in everyday settings, such
as whether a particular event or behavior typically precedes another. Such observations can help
researchers determine which behaviors are important to study in the first place. A scientist who studies
bullying by observing children’s play may notice that some victims act aggressively
a bullying
encounter (Kamper-DeMarco & Ostrov, 2017). The scientist may then decide to examine aggression in
victims not only after a bullying incident but also beforehand. Naturalistic observation is a useful way of
studying events and behaviors that are common. Some behaviors and events are uncommon or are
difficult to observe, such as physical aggression among adults, requiring a researcher to observe for very
long periods of time to obtain data on the behavior of interest. For this reason, many researchers make
structured observations.
before
This researcher is using a video camera to observe and record the facial
expressions a newborn baby makes while they sleep.
Thierry Berrod, Mona Lisa Production/Science Source
Structured observation entails observing and recording behaviors displayed in a controlled
environment, a situation constructed by the experimenter. Children might be observed in a laboratory
setting as they play with another child or complete a puzzle-solving task. The challenges of identifying
and categorizing which behaviors to record are similar to those involved in naturalistic observation.
However, the laboratory environment permits researchers to exert more control over the situation than
is possible in natural settings. In addition to cataloging observable behaviors, some researchers use
technology to measure biological functions such as heart rate, brain waves, and blood pressure. One
challenge to conducting structured observations is that people do not always behave in laboratory
settings as they do in real life.
Self-Report Measures
Interviews and questionnaires are known as self-report measures because the person under study
answers questions about his or her experiences, attitudes, opinions, beliefs, and behavior. Interviews can
take place in person, over the phone, or over the Internet.
One type of interview is the open-ended interview, in which a trained interviewer uses a conversational
style that encourages the participant, or the person under study, to expand his or her responses.
Interviewers may vary the order of questions, probe, and ask additional questions based on responses.
The scientist begins with a question and then follows up with prompts to obtain a better view of the
person’s reasoning (Ginsburg, 1997). An example of this is the Piagetian Clinical Interview, which requires
specialized training to administer. Consider this dialogue between Piaget and a 6-year-old child:
You know what a dream is?
When you are asleep and you see something
Where does it come from?
The sky
Can you see it?
No! Yes, when you’re asleep
Could I see it if I was there?
No.
Why not?
Because it is in front of us…. When you are asleep you dream and you see them, but when you
aren’t asleep you don’t see them.
(Piaget, 1929, p. 93)
Open-ended interviews permit participants to explain their thoughts thoroughly and in their own words.
They also enable researchers to gather a large amount of information quickly. Open-ended interviews
are very flexible as well. But their flexibility poses a challenge: When questions are phrased differently
for each person, responses may not capture real differences in how people think about a given topic and
instead may reflect differences in how the questions were posed and followed up by the interviewer.
The interviewer may ask a child about their own experiences, opinions, and
behavior. Interviews and questionnaires are known as self-report measures.
damircudic/Getty Images
In contrast, a structured interview poses the same set of questions to each participant in the same way.
On the one hand, structured interviews are less flexible than open-ended interviews. On the other hand,
because all participants receive the same set of questions, differences in responses are more likely to
reflect true differences among participants and not merely differences in the manner of interviewing.
Evans et al. (2002) used a structured interview to examine American children’s beliefs about magic.
Children between the ages of 3 and 8 were asked the following set of questions:
What is magic? Who can do magic?
Is it possible to have special powers? Who has special powers?
Does someone have to learn to do magic? Where have you seen magic? (p. 49)
After compiling and analyzing the children’s responses as well as administering several cognitive tasks,
the researchers concluded that even older children, who have the ability to think logically and perform
concrete operations, may display magical beliefs.
To collect data from large samples of people, scientists may compile and use questionnaires, also called
surveys, made up of sets of questions, typically multiple choice. Questionnaires can be administered in
person, online, or by telephone, email, or postal mail. Questionnaires are popular data collection
methods because they are easy to use and enable scientists to collect information from many people
quickly and inexpensively. Scientists who conduct research on sensitive topics, such as sexual interest
and experience, often use questionnaires because they can easily be administered anonymously,
protecting participants’ privacy. The Monitoring the Future Study is an annual survey of 50,000 8th-,
10th-, and 12th-grade students that collects information about their behaviors, attitudes, and values
concerning drug and alcohol use (Miech et al., 2017). The survey permits scientists to gather an
enormous amount of data yet its anonymity protects the adolescents from the consequences of sharing
personal information that they might not otherwise reveal.
Despite their ease of use, self-report measures are not without challenges. Questionnaires rely on a
person’s ability to read and understand questions and provide responses. Children and individuals who
are capacitated may have difficulty completing questionnaires. Sometimes people give socially desirable
answers: They respond in ways they would like themselves to be perceived or believe researchers desire.
A college student completing a survey about cheating might sometimes look at nearby students’ papers
during examinations, but she might choose survey answers that do not reflect this behavior. Her answers
might instead match the person she aspires to be or the behaviors she believes the world values—that
is, someone who does not cheat on exams. Self-report data, then, may not always reflect people’s true
attitudes and behavior. Some argue that we are not always fully aware of our feelings and therefore
cannot always provide useful insight into our own thoughts and behavior with the use of self-report
measures (Newell & Shanks, 2014).
Physiological Measures
Our body responses are an important source of information that can be used to understand
psychological phenomena. Physiological measures offer important information increasingly used in
developmental research because cognition, emotion, and behavior have physiological indicators. Do you
feel your heart beat more rapidly or your palms grow sweaty when you give a class presentation?
Increases in heart rate and perspiration are physiological measures of anxiety. Other researchers might
measure cortisol, a hormone triggered by the experience of stress (Simons et al., 2017).
Eye movements and pupil dilation can indicate attention and interest. Researchers who tracked
participants’ eye movements as they viewed Facebook feeds learned that people are naturally attracted
to social and news posts that are rich with pictures and links, yet most people are unable to report what
they have viewed, even immediately after viewing it (Vraga et al., 2016). Researchers who employ
physiological measures might use pupil dilation as a measure of interest in infants and physiological
arousal in adults (Feurer et al., 2017; Wetzel et al., 2016).
Physiological measures of brain activity are a particularly promising source of data. Several tools are
used to study the brain. Electroencephalography (EEG) measures electrical activity patterns produced by
the brain via electrodes placed on the scalp. Researchers study fluctuations in activity that occur when
participants are presented with stimuli or when they sleep. EEG recordings measure electrical activity in
the brain, but they do not provide information about the location of activity or the brain structures that
are the source of brain activity.
Computerized tomography (CT scan) compiles multiple x-ray images to create a three-dimensional
picture of a person’s brain, providing images of brain structures, bone, brain vasculature, and tissue
(Cierniak, 2011). CT scans can provide researchers with information about the density of brain structures
to illustrate how the thickness of the cortex changes with development. Recording multiple x-ray images,
however, exposes research participants to higher levels of radiation than a single x-ray (Davies et al.,
2011).
Positron emission tomography (PET) involves injecting a small dose of radioactive material into the
participant’s bloodstream to monitor the flow of blood (Portnow et al., 2013). Blood flows more readily
to active areas of the brain and the resulting images can illustrate what parts of the brain are active as
participants view stimuli and solve problems.
Functional magnetic resonance imaging (fMRI) measures brain activity with a powerful magnet that
uses radio waves and to measure blood oxygen level (Bandettini, 2012). Active areas of the brain require
more oxygen-rich blood, permitting researchers to determine what parts of the brain are active as
individuals complete cognitive tasks. fMRI images are much more detailed than PET scans and do not
rely on radioactive molecules, which can only be administered a few times before becoming unsafe.
Diffusion tensor imaging (DTI) uses an MRI machine to track how water molecules move in and around
the fibers connecting different parts of the brain (Soares et al., 2013). DTI gauges the thickness and
density of the brain's connections, permitting researchers to measure the brain’s white matter and
determine changes that occur with development.
An advantage of physiological measures is they do not rely on verbal reports and generally cannot be
faked. A challenge to physiological measures is that, although physiological responses can be recorded,
they may be difficult to interpret. Excitement and anger may both cause an increase in heart rate. Data
collection methods are summarized in Table 1.5.
Table 1.5 Data Collection Methods
Advantage
Observational Measures
Disadvantage
Advantage
Naturalistic observation Gathers data on everyday behavior in a
natural environment as behaviors occur.
Structured observation
Self-Report Measures
Open-ended interview
Observation in a controlled setting.
Gathers a large amount of information
quickly and inexpensively.
Structured interview
Gathers a large amount of information
quickly and inexpensively.
Questionnaire
Gathers data from a large sample more
quickly and inexpensively than by interview
methods.
Physiological Measures
Disadvantage
The observer’s presence may
influence participants'
behavior. No control over the
observational environment.
May not reflect real-life
reactions and behavior.
Nonstandardized questions.
Characteristics of the
interviewer may influence
participant responses.
Characteristics of the
interviewer may influence
participants' responses.
Some participants may
respond in socially desirable
or inaccurate ways.
May be expensive, difficult for
Assesses biological indicators and does not researchers to access, and
rely on participant report.
difficult to interpret
Difficult to fake responses.
Electroencephalography Measures electrical activity patterns
(EEG)
produced by the brain
Computerized
tomography (CT scan)
Positron emission
tomography (PET)
Functional magnetic
resonance imaging
(fMRI)
Diffusion tensor
imaging (DTI)
Provides images of brain structures, bone,
brain vasculature, and tissue
Illustrates activity in specific parts of the
brain as participants complete cognitive
tasks
Illustrates activity in specific parts of the
brain as participants complete cognitive
tasks. More detailed images than PET scans
and does not rely on radiation
Measures the thickness and density of
brain connections. Less expensive than
fMRI
Does not provide information
about the brain structures that
are the source of brain activity
Exposes participants to low
levels of radiation
Exposes participants to low
levels of radiation
Expensive and requires
participants to be completely
still during the scan
Requires participants to be
completely still during the
scan
Research Designs
Just as there are many ways to collect information, scientists have many options for conducting their
studies. In addition to determining the research question and deciding what information to collect,
scientists must choose a research design—a technique for conducting the research study.
Case Study
A case study is an in-depth examination of a single person (or small group of individuals). It is
conducted by gathering information from many sources, such as through observations, interviews, and
conversations with family, friends, and others who know the individual. A case study may include
samples or interpretations of a person’s writing, such as poetry or journal entries, artwork, and other
creations. A case study provides a rich description of a person’s life and influences on his or her
development. It is often employed to study individuals who have unique and unusual experiences,
abilities, or disorders. Conclusions drawn from a case study may shed light on an individual’s
development but may not be generalized or applied to others. Case studies can be a source of
hypotheses to examine in large-scale research.
Correlational Research
Are children with high self-esteem more likely to excel at school? Are older adults with more friends
happier than those with few? Are college students who work part-time less likely to graduate? All of
these questions can be studied with correlational research, which permits researchers to examine
relations among measured characteristics, behaviors, and events. In one study scientists examined the
relationship between physical fitness and academic performance in middle school students and found
that children with higher aerobic capacity scored higher on achievement tests than did children with
poorer aerobic capacity (Bass et al., 2013). Note that this correlation does not tell us
aerobic
capacity was associated with academic achievement. Correlational research cannot answer this question
because it simply describes relationships that exist among variables; it does not enable us to reach
conclusions about the causes of those relationships. It is likely that other variables influence both a
child’s aerobic ability and achievement (e.g., health), but correlation does not enable us to determine the
causes for behavior—for that we need an experiment.
why
Researchers experimentally manipulate which children play with violent video
games to determine their effect on behavior.
istock/sakkmesterke
Experimental Research
causal
Scientists who seek to test hypotheses about
relationships, such as whether media exposure
influences behavior or whether hearing particular types of music influences mood, employ experimental
research. An experiment is a procedure that uses control to determine causal relationships among
variables. Specifically, one or more variables thought to influence a behavior of interest are changed, or
manipulated, while other variables are held constant. Researchers can then examine how the changing
variable influences the behavior under study. If the behavior changes as the variable changes, this
suggests that the variable caused the change in the behavior.
Gentile et al. (2017) examined the effect of playing violent video games on children’s physiological stress
and aggressive thoughts. Children were randomly assigned to play a violent video game (
) or
Superman
Finding Nemo
a nonviolent video game (
) for 25 minutes in the researchers’ lab. The researchers
measured physiological stress as indicated by heart rate and cortisol levels before and after the children
played the video game. Children also completed a word completion task that the researchers used to
measure the frequency of aggressive thoughts. The researchers found that children who played violent
video games showed higher levels of physiological stress and aggressive thoughts than did the children
who played nonviolent video games. They concluded that the type of video game changed children’s
stress reactions and aggressive thoughts.
Let’s take a closer look at the components of an experiment. Conducting an experiment requires
choosing at least one dependent variable, the behavior under study (e.g., physiological stress—heart
rate and cortisol—and aggressive thoughts), and one independent variable, the factor proposed to
change the behavior under study (e.g., type of video game). The independent variable is manipulated or
varied systematically by the researcher during the experiment (e.g., a child plays with a violent or a
nonviolent video game). The dependent variable is expected to change as a result of varying the
independent variable, and how it changes is thought to depend on how the independent variable is
manipulated (e.g., physiological stress and aggressive thoughts vary in response to the type of video
game).
After the independent variable is manipulated, if the experimental and control groups differ on the
dependent variable, it is concluded that the independent variable
the change in the dependent
variable. That is, a cause-and-effect relationship has been demonstrated.
caused
experimental groups
In an experiment, the independent variable is administered to one or more
, or test
groups. The
is treated just like the experimental group except that it is not exposed to the
independent variable. In an experiment investigating whether particular types of music influence mood,
the experimental group would experience a change in music (e.g., from “easy listening” to rock), whereas
the control group would hear only one type of music (e.g., “easy listening”). Random assignment,
whereby each participant has an equal chance of being assigned to the experimental or control group, is
essential for ensuring that the groups are as equal as possible in all preexisting characteristics (e.g., age,
ethnicity, and gender). Random assignment makes it less likely that any observed differences in the
outcomes of the experimental and control groups are due to preexisting differences between the
groups. After the independent variable is manipulated, if the experimental and control groups differ on
the dependent variable, it is concluded that the independent variable
the change in the
dependent variable. That is, a cause-and-effect relationship has been demonstrated.
control group
caused
As another example, consider a study designed to examine whether massage therapy improves
outcomes in preterm infants (infants who were born well before their due date) (Abdallah et al., 2013).
Infants housed in a neonatal unit were assigned to a massage group (independent variable), who were
touched and their arms and legs moved for 10-minute periods once each day, or to a control group,
which received no massage. Other than the massage/no massage periods, the two groups of infants
were cared for in the same way. Infants who were massaged scored lower on the measure of infant pain
and discomfort (including indicators such as heart rate, oxygen saturation, and facial responses) at
discharge (dependent variable). The researchers concluded that massage therapy reduces pain
responses in preterm infants.
Developmental scientists conduct studies that use both correlational and experimental research.
Studying development requires that scientists pay close attention to age and how people change over
time, which requires the use of specialized research designs, as described in the following sections.
Developmental Research Designs
Does personality change over the lifespan? Do children outgrow shyness? Are infants’ bonds with their
parents associated with their adult relationships? These questions require that developmental scientists
examine relationships among variables over time. The following sections discuss the designs that
researchers use to learn about human development. As you learn about each design, consider how we
might employ it to answer a question about development. How does alcohol use among adolescents
change from 6th grade through 12th grade?
Cross-Sectional Research Design
A cross-sectional research study compares groups of people of different ages at a single point in time.
Suppose a researcher wanted to know how alcohol use changes from early to late adolescence, from
age 12 to 18. To study this question the researcher might visit a school system in 2022 and administer a
survey about alcohol use to students ages 12, 14, 16, and 18. By analyzing the survey, the scientist can
describe
in alcohol use and identify how 12-year-olds differ from 18-year-olds today.
However, the results do not tell us whether the observed age differences in alcohol use reflect agerelated or developmental change. In other words, we do not know whether the 12-year-olds in this
sample will show the same patterns of alcohol use as the current 18-year-olds when they are 18, six
years from now.
age differences
Cross-sectional research permits age comparisons, but participants differ not only in age but in cohort. A
cohort is a group of people of the same age who are exposed to similar historical events and cultural
and societal influences. Cohorts refer to generations, but we can also speak of smaller cohorts based on
factors such as the year of entry to school. In this example, the 12-year-olds and the 18-year-olds are
different ages, but they are also in different cohorts, so the two groups may differ in reported alcohol
use because of development (age-related changes) or cohort (group-related changes). Perhaps the 12year-olds received a new early prevention program at school that was not available to the 18-year-olds
when they were 12. The difference in alcohol use between 12-year-olds and 18-year-olds might then be
related to the prevention program, a cohort factor, and not to age. Cross-sectional research is an
important source of information about age differences, but it cannot provide information about agerelated changes because participants are assessed only once.
Longitudinal Research Design
A longitudinal research study follows the same group of participants over many points in time.
Returning to the previous example, to examine how alcohol use changes from 12 to 18 years of age, a
developmental scientist using longitudinal research might administer a survey on alcohol use to 12year-olds and then follow up two years later when they are 14, again when they are 16, and finally when
they are 18. If a researcher began this study in 2022, the last round of data collection would not occur
until 2028.
Longitudinal research provides information about age-related change because it follows individuals over
time, enabling scientists to describe how the 12-year-olds’ alcohol use changed as they progressed
through adolescence. However, longitudinal research studies only one cohort, calling into question
whether findings indicate developmental change or whether they are an artifact of the cohort under
study. Was the group of 12-year-olds that the scientist chose to follow for six years somehow different
from the cohorts or groups of students who came before or after? Because only one cohort is assessed,
it is not possible to determine whether the observed changes are age-related changes or changes that
are unique to the cohort examined.
Sequential Research Designs
A sequential research design combines the best features of cross-sectional and longitudinal research by
assessing multiple cohorts over time, enabling scientists to make comparisons that disentangle the
effects of cohort and age (Figure 1.7). Consider the alcohol use study once more. A sequential design
would begin in 2022 with a survey to students ages 12, 14, 16, and 18. Two years later, in 2024, the initial
sample is surveyed again; the 12-year-olds are now 14, the 14-year-olds are now 16, and the 16-yearolds are now 18. The 18-year-olds are now 20 and are not assessed, because they have aged out of the
study. Now a new group of 12-year-olds is surveyed. Two years later, in 2026, the participants are
surveyed again, and so on.
The sequential design provides information about age, cohort, and age-related change. The crosssectional data (comparisons of 12-, 14-, 16-, and 18-year-olds from a given year) provide information
about age differences, how the age groups differ from one another. The longitudinal data (annual
follow-up of participants ages 12 through 18) captures age-related change because participants are
followed up over time. The sequential component helps scientists separate cohort effects from agerelated change. Because several cohorts are examined at once, the effect of cohort can be studied. The
sequential design is complex, but it permits human development researchers to disentangle the effects
of age and cohort, and answer questions about developmental change.
Description
Figure 1.7 Sequential Research Design
Source: Kim & Böckenholt (2000).
Table 1.6 Comparing Research Designs
Design
Strengths
Research Designs
Case study
Provides a rich description of an individual.
Correlational Permits the analysis of relationships among
variables as they exist in the real world.
Limitations
Conclusions may not be generalized
to other individuals.
Cannot determine cause-and-effect
relations.
Design
Strengths
Experimental Permits a determination of cause-and-effect
relations.
Developmental Research Designs
CrossMore efficient and less costly than the
sectional
longitudinal design. Permits the determination
of age differences.
Longitudinal Permits the determination of age-related
changes in a sample of participants assessed
for a period of time.
Sequential
Permits thorough analyses of developmental
change. Simultaneous longitudinal and crosssectional comparisons reveal age differences
and age change, as well as cohort effects.
Limitations
Data collected in artificial
environments may not represent
behavior in real-world environments.
Does not permit inferences regarding
age change. Confounds age and
cohort.
Time-consuming and expensive.
Participant attrition may limit
conclusions. Cohort-related changes
may limit the generalizability of
conclusions.
Time-consuming, expensive, and
complicated data collection and
analysis.
In summary, scientists use the scientific method to systematically ask and seek answers to questions
about human development. Researchers’ decisions about measures and research designs influence the
information that they collect and the conclusions that they make about development. Table 1.6
summarizes the research designs available to developmental scientists. Researchers have responsibilities
to conduct sound research and also to adhere to standards of ethical conduct in research, as the next
section describes.
Thinking in Context: Applied Developmental Science
Lua is interested in understanding academic achievement in elementary school students. Specifically, she
believes that too much screen time harms students’ achievement.
1. How might Lua gather information to address her hypothesis?
2. What are some of the challenges of measuring behaviors such as screen time?
3. What kind of research design should Lua use? What are the advantages and disadvantages of this
design?
4. Suppose Lua wanted to know the long-term correlates of screen time. How might she study this
question?
RESEARCH ETHICS
LEARNING OBJECTIVE
1.5 Discuss principles of research ethics and the ethical issues that may arise in developmental
science research.
Suppose a researcher wanted to study the effects of bullying on emotional development or determine
how malnutrition influences development. Would it be possible to design a study in which some
children are exposed to bullying or some kindergarteners are deprived of food? Of course not. These
studies violate the basic ethical principles that guide developmental scientists’ work, as described below.
Principles of Research Ethics
In addition to conducting research that is scientifically sound, developmental scientists must adhere to
standards of ethical conduct in research. Several basic ethical principles guide developmental scientists’
work: (1) do good and avoid harm, (2) responsibility, (3) integrity, (4) justice, and (5) respect for
autonomy (American Psychological Association, 2010; Society for Research in Child Development, 2021).
Developmental scientists are obligated to do good and to avoid doing harm. Researchers must protect
and help the individuals, families, and communities they work with by maximizing the benefits and
minimizing the potential harms of their work. Participating in research must never pose threats to
individuals beyond those they might encounter in everyday life. Researchers also have the responsibility
to help participants by directing a distressed participant toward help-seeking resources.
A second principle that guides developmental scientists’ work is that they must act responsibly by
adhering to professional standards of conduct, clarifying their obligations and roles to others, and
avoiding conflicts of interest. A psychologist who conducts research with children and parents must
clarify her role as scientist and not counselor and help her participants understand that she is simply
gathering information from them rather than conducting therapy.
Researchers’ responsibility extends beyond their participants to society at large to ensure that their
research findings are accurately portrayed in the media. The principle of responsibility means that
researchers must attempt to foresee ways in which their results may be misinterpreted and correct any
misinterpretations that occur (Lilienfeld, 2002; Society for Research in Child Development, 2021).
Sometimes researchers’ findings have social and political implications that they may not expect. For
example, one highly publicized study compiled the results of many research studies examining college
students who had become sexually involved with an adult prior to reaching the legal age of consent
(Rind et al., 1998). After examining the body of research, the scientists determined that young people’s
coping and development varied depending on a number of factors within the individual, situation, and
broader context; not all the young people appeared to be equally harmed. Participants who were older
when the relationship began, such as in late adolescence, just prior to reaching the age of consent,
showed fewer negative effects and appeared well-adjusted. These findings were misinterpreted by some
organizations, media outlets, and politicians as suggesting that sexual involvement with minors was
acceptable or even beneficial—clearly not the researchers’ conclusions (Garrison & Kobor, 2002).
The principle of integrity requires that scientists be accurate, honest, and truthful in their work by being
mindful of the promises they make to participants and making every effort to keep their promises to the
people and communities with which they work. Researchers should recognize the participants’ right to
learn about the results of their research. In addition, the risks and benefits of research participation must
be spread equitably across individuals and groups. This is the principle of justice. Every participant
should have access to the contributions and benefits of research. When a treatment or intervention
under study is found to be successful, all participants must be given the opportunity to benefit from it.
Perhaps the most important principle of research ethics is respect for autonomy. Scientists have a special
obligation to respect participants’ autonomy, their ability to make and implement decisions. Ethical
codes of conduct require that researchers protect participants’ autonomy by obtaining informed
consent—participants’ informed, rational, and voluntary agreement to participate. Soliciting informed
consent requires providing the individuals under study information about the research study, answering
questions, and ensuring that they understand that they are free to decide not to participate in the
research study and that they will not be penalized if they refuse.
Ethical Issues in Studying Lifespan Human Development
Each period in the lifespan poses unique ethical concerns for researchers. Common and pressing ethical
challenges include soliciting consent, maintaining participant confidentiality, and protecting participants
from harm.
Informed Consent
Respecting people’s autonomy also means protecting those who are not capable of making judgments
and asserting themselves. Parents provide parental permission for their minor children to participate
because researchers (and lawmakers) assume that minors are not able to meet the rational criteria of
informed consent. Although children cannot provide informed consent, researchers respect their
growing capacities for decision making in ways that are appropriate to their age by seeking child assent,
children’s agreement to participate (Tait & Geisser, 2017). For toddlers or young children, obtaining
assent may involve simply asking if they want to play with the researcher (Brown et al., 2017). With
increasing cognitive and social development, children are better able to understand the nature of
science and engage meaningfully in decisions about research participation. Discussions about research
participation should be tailored to children’s development, including offering more detailed information
and seeking more comprehensive assent as children grow older (Roth-Cline & Nelson, 2013). Moreover,
seeking assent has the benefit of helping children learn how to make decisions and participate in
decision making within safe contexts (Oulton et al., 2016).
Studying adolescents often raises unique ethical questions because they are minors, generally requiring
parental consent. Adolescent research participants are often very concerned about how their
information and samples will be used, and in particular, whether information would be shared with their
parents (Crane & Broome, 2017). Sometimes seeking consent from parents may interfere with
researchers’ goals or may pose risks to minor participants. In one study, LGBT adolescents believed that
participating in research on sexuality and health is important for advancing science, yet they indicated
that they would not participate if guardian permission was required, citing negative parental attitudes or
not being “out” about their LBGT identity (Macapagal et al., 2017). As one 15-year-old bisexual
participant explained:
I believe it could harm some [teens] because the risk of being let out of the closest. I know
some people whose family would not approve of any other sexuality [other than
heterosexuality]. Such as my own, my mother would turn on me for not being her perfect
image.
In response to these ethical challenges, researchers frequently obtain passive consent for conducting
research on sensitive topics with adolescents. Passive consent procedures typically involve notifying
parents about the research and requiring them to reply if they do
want their child to participate.
Studies that examine sensitive topics, such as risk behaviors, may benefit from the use of passive
consent procedures because they are associated with more diverse samples of adolescents that better
represent the population (Liu et al., 2017).
not
In addition to minors, adults sometimes require accommodations for providing informed consent.
Traumatic brain injury, dementia, mental illness, some physical illnesses, and advanced age can impair
adults’ capacities to provide informed consent (Prusaczyk et al., 2017). In such cases, researchers seek
assent by providing the participant with meaningful information in a format that they can understand (as
well as obtaining consent from a surrogate decision maker). Cognitive capacities can often fluctuate and,
in the case of traumatic brain injury patients, often improve (Triebel et al., 2014). Researchers must be
prepared to tailor their explanations to the participant’s fluctuating competence.
Confidentiality
Ethical issues may arise when researchers’ desire to learn about development and solve problems
conflicts with their need to protect research participants. Researchers generally promise participants
confidentiality, that their responses will remain confidential and will not be disclosed to others. Suppose
a researcher studying adolescents learns that a participant is in jeopardy, whether engaging in healthcompromising behaviors (e.g., cigarette smoking, unsafe driving, or unhealthy behavior), contemplating
suicide, or engaging in illegal or harmful activities (e.g., drug addiction, stealing, or violence). Is the
researcher responsible for helping the adolescent? Does the researcher have a duty to disclose the risk
to an outside party who can help the adolescent, such as parents? Does the researcher’s promise of
confidentiality outweigh the duty to disclose? Adolescents and parents tend to have different opinions
about research disclosures; parents often want to receive their children’s research information, but
adolescents tend to report wanting to withhold private and sensitive findings (Brawner et al., 2013).
expect
Researchers who study risky and health-compromising behaviors
to encounter participants who
are engaged in potentially dangerous activities. Helping the adolescent might involve removing him or
her from the study and potentially compromising the study. Adolescents generally expect that
researchers will maintain confidentiality (Fisher et al., 1996); violating their confidentiality may be
harmful.
Issues with confidentiality are common when studying adolescents, but they arise throughout the
lifespan. Suppose a researcher is studying older adults in a nursing home and discovers illicit substance
dependence in an adult who is also taking many medications. Or a sexual relationship in an adult who
experiences bouts of dementia. Or suicidal thoughts in a middle-aged parent.
Ethical guidelines published by research and medical associations address researchers’ obligations to
help and not harm and to protect participants’ confidentiality, but they generally fail to offer specific
recommendations about how researchers can manage the conflicting duties to maintain confidentiality
and disclose participant problems (Hiriscau et al., 2014; Sharkey et al., 2017). Instead, researchers must
decide for themselves how to balance their sometimes conflicting obligations to their participants. Table
1.7 summarizes the rights of research participants.
Table 1.7 Rights of Research Participants
Right
Protection
from harm
Description
Research participants have the right to be protected from physical and psychological
harm. Investigators must use the least stressful research procedure in testing
hypotheses and, when in doubt, consult with others.
Informed
Participants have the right to be informed about the purpose of the research,
consent
expected duration, procedures, risks and benefits of participation, and any other
aspects of the research that may influence their willingness to participate. When
children are participants, a parent or guardian must provide informed consent on
behalf of the child, and the investigator should seek assent from the child.
Confidentiality Participants have the right to privacy and to conceal their identity on all information
and reports obtained in the course of research.
Information
Participants have the right to be informed of the results of research in language that
about the
matches their level of understanding.
results
Treatment
If an experimental treatment under investigation is believed to be beneficial,
participants in control groups have the right to obtain the beneficial treatment.
Sources: American Psychological Association (2010); Society for Research in Child Development, 2021.
Thinking in Context: Applied Developmental Science
1. Suppose, as part of your research, you wanted to interview children at school. What ethical
principles are most relevant to examining school children? What challenges do you anticipate in
conducting this work?
2. You are tasked with collecting observations and interviews of older adults to evaluate a health
program at a nursing home. What ethical issues can you anticipate? What principles are most
pertinent?
Thinking in Context: Intersectionality
Some ethical concerns are more pressing for some participants and in some studies more than others.
Consider a study examining sexuality. People of different ages and characteristics might vary in their
concerns about confidentiality in sexuality research.
1. To what extent do you think adolescents, adults, and older adults might vary in their concerns
about sharing their sexual interests, beliefs, and behaviors?
2. What other variables might be associated with different perspectives on the value of
confidentiality? Might you expect cultural differences in concerns about confidentiality? Might
factors like sexual orientation, religion, gender, or ethnicity relate to concerns about confidentiality
in sexuality research? Why or why not?
APPLIED DEVELOPMENTAL SCIENCE AND INTERSECTIONALITY
LEARNING OBJECTIVE
1.6 Describe the field of applied developmental science and the role of intersectionality in
development.
In its early years, the study of human development emphasized laboratory research devoted to
uncovering universal aspects of development by stripping away contextual influences. This
was designed to examine how development unfolds, with the assumption that development is
a universal process with all people changing in similar ways and in similar time frames. In the early
1980s, influenced by contextual theories (such as Bronfenbrenner’s bioecological approach) and the
growing assumption that people are active in their development (a cornerstone of lifespan
developmental theory), developmental scientists began to examine developmental processes outside of
the laboratory (Lerner et al., 2015). As developmental scientists engaged in
, it quickly
became apparent that there are a great many individual differences in development that vary with a
myriad of contextual influences. We also learned that developmental research findings can be applied to
improve people’s lives.
research
basic
applied research
Applied Developmental Science
Applied developmental science is a field of study that examines the lifelong developmental interactions
among individuals and their contexts and applies these findings to prevent and intervene in problems
and promote positive development (Fisher et al., 2013). Applied developmental scientists study pressing
social issues, such as promoting the development of preterm infants, determining children’s capacity to
provide courtroom testimony, promoting safe sex in adolescents and emerging adults, and aiding older
adults’ and their adult children’s adjustment to disability (Fisher et al., 2013; Lerner, 2012). By its very
nature, applied developmental science is multidisciplinary because real-world problems are complex and
require the expertise of scientists from many fields, such as human development, psychology, medicine,
biology, anthropology, and more.
Applied developmental scientists are especially interested in promoting healthy development over the
lifespan. That is, they seek to enhance the life chances of diverse groups of individuals, families, and
communities. Many children, adolescents, and adults are affected by social problems that can impede
healthy development, such as hunger, poor nutrition, pervasive poverty, and inadequate access to
education, health care, and community services (Aizer, 2017; Gauvain, 2018; Golinkoff et al., 2017;
Huston, 2018). It is through applied research that scientists have come to appreciate the full range of
contextual influences on development and how lifelong opportunities and outcomes vary with factors
such as sex, ethnicity, socioeconomic status, and age.
Applied developmental scientists also work to understand and address the systemic disparities in
opportunities that people experience over the lifespan (Fisher et al., 2012). They seek to promote equity
and social justice, the basic human right of individuals to have access to opportunities, experiences, and
resources that maximize their potential for growth, health, and happiness across the life course (Brown
et al., 2019; Smith & Smith Lee, 2019). Individuals’ access to support and opportunity varies dramatically
with race, sex, and other factors. Equity and social justice involve recognizing and addressing these
disparities and the complex factors that contribute to them.
Intersectionality and Development
We are all members of multiple intertwined social categories, such as gender, race, age, and sexual
orientation. Our understanding and experience of each category is influenced by our membership in
other categories. Adolescents’ understanding and experience of gender may be filtered through the lens
of their membership in another social category, such as ethnicity. Latina girls’ views of themselves and
their worlds may be quite different from those of Latino boys as well as girls of other ethnicities, such as
Black and white girls. In this example the intersection of ethnicity and gender combine to influence girls’
self-understanding and experience. Power and opportunity are enmeshed with social categories, such as
ethnicity and gender. Latina girls’ views of themselves reflect not simply their sex and ethnicity but the
relative power ascribed to girls and persons of color in U.S. society.
Our unique experiences and perspectives are influenced by intersectionality, the dynamic interrelations
of social categories—gender, race and ethnicity, sexual orientation, socioeconomic status, immigration
status, age, and disabilities—and the interwoven systems of power and privilege that accompany social
category membership (Crenshaw, 1989). An intersectional perspective draws attention to inequities in
power, opportunity, privilege, and disadvantage that accompany social category membership and are
experienced as racism, sexism, classism, heterosexism, and more, to shape individuals’ lived experiences
(Roy, 2018; Santos & Toomey, 2018; Syed & Ajayi, 2018).
Central to intersectionality are the assumptions that (1) all individuals have multiple identities that
converge, (2) within each identity is a dimension of power or oppression, and (3) identities are
influenced by the sociocultural context (Abrams et al., 2020; Else-Quest & Hyde, 2016). Identities overlap
and systems of oppression, such as racism and sexism, may interlock. Individuals therefore experience
multiple overlapping identities and may struggle against intertwined systems of oppression and bias
(Rosenthal, 2016).
The effects of social category membership are not experienced universally, but they vary with context
(Ghavami et al., 2016; Godfrey & Burson, 2018). Intersectionality is inherently tied to context. Social
categories such as gender, race, and sexual orientation may be more salient and meaningful in some
contexts and at some times than others, creating distinct experiences for subgroup members with
implications for development (Crenshaw, 1989; Syed & Ajayi, 2018). For instance, intersecting
expectations about race and gender may uniquely shape the experience of Black boys in classroom
settings, how they are perceived and treated, that is unique from those experienced by boys of other
races and ethnicities and the experiences of Black girls—with implications for their academic
performance, development, and long-term outcomes (Roy, 2018). Likewise, Black boys’ classroom
experiences might vary with context, whether rural, suburban, or urban, and part of the United States,
such as the North, South, Midwest, and coasts.
Until recently, people of color have been largely excluded from research studies or research participants
of all ethnicities and races have been grouped, masking differences and contributing to a sense of
invisibility among people of color (Grzanka, 2020; Roberts et al., 2020; Syed et al., 2018). One analysis of
articles published between 2006 and 2010 in leading developmental science journals (
,
, and
) found that only 14% included samples that
were predominantly people of color and a surprisingly high 28% did not mention the racial/ethnic
composition at all (Nielsen et al., 2017).
Psychology Child Development
Developmental Science
Developmental
The study of intersectionality sheds light on how discrimination, marginalization, oppression, and
privilege combine to influence individuals’ experiences in unique ways across the lifespan (Crenshaw,
1989). Intersectionality is an emerging approach in developmental science with a small but rapidly
growing body of research that recognizes the many ways that gender, ethnicity and race, sexual
orientation, socioeconomic status, and disability interact to influence development (Godfrey & Burson,
2018; Grzanka, 2020). Throughout this book we will examine development through an intersectional lens
whenever possible.
These students attend the same school, but their experiences may vary
greatly with intersectional factors such as race, ethnicity, and gender.
iStock/franz12
Thinking in Context: Intersectionality
1. Consider the social categories of which you are a member (perhaps gender, race or ethnicity,
socioeconomic status, or religion). Which are most important to you? How might these social
categories interact to influence your experiences?
2. Consider our discussion of research methods earlier in this chapter. What are some of the
challenges of studying the real-world problems addressed by applied developmental science? Do
any special considerations arise when studying development through an intersectional lens?
APPLY YOUR KNOWLEDGE
1.
Steven enters the school psychologist’s office with a frown, grumbling to himself. His teacher, Ms.
Marta, has suggested that he visit the school psychologist for help understanding and treating his
academic problems. Steven is a bright fifth grader, but he has great difficulties reading and his
mathematics skills lag far behind his peers. Ms. Marta contacts Steven’s mother, reassuring her that
the school has excellent resources for diagnosing children’s learning problems and special
education professionals who can intervene and help children overcome learning difficulties.
The school psychologist interviews Steven’s mother in order to compile a history of Steven’s
development. Through this interview, he learns that Steven suffered a great deal of trauma early in
life; as an infant, he was physically abused by his biological mother, then taken away and placed in
foster care. At age 3, he was adopted into a middle-class, suburban family with two older,
nonadopted children.
As we have seen, each developmental theory has a unique emphasis. How might each theory
address Steven’s academic difficulties?
a. What factors would psychoanalytic theories point to in order to explain Steven’s functioning?
b. How would cognitively oriented theories, such as Piaget’s cognitive–developmental theory and
information processing theory, account for and intervene with Steven’s difficulties?
c. Identify contextual factors that may play a role in Steven’s academic problems; from
Bronfenbrenner’s bioecological theory, what factors may be addressed?
2.
Suppose you wanted to conduct research on academic achievement during elementary and middle
school.
a. Identify a research question appropriate for a correlational research study.
b. How would you address that question with a cross-sectional research study? Longitudinal?
Sequential?
c. What are the advantages and disadvantages of each type of study?
CHAPTER SUMMARY
1.1
Outline five principles of the lifespan developmental perspective.
Development is a lifelong process. It is multidimensional, multidirectional, plastic, influenced by the
multiple contexts in which we are embedded, and multidisciplinary.
1.2
Explain three basic issues in developmental science.
Developmental scientists take different perspectives on three views. First, in what ways is
developmental change continuous, characterized by slow and gradual change, or discontinuous,
characterized by sudden and abrupt change? Second, to what extent do people play an active role
in their own development, interacting with and influencing the world around them? Finally, is
development caused by nature or nurture? Most developmental scientists agree that some aspects
of development appear continuous and others discontinuous, that individuals are active in
influencing their development, and that development reflects the interactions of nature and
nurture.
1.3
Summarize five theoretical perspectives on human development.
Psychanalytic theories emphasize inner drives. Freud’s psychosexual theory explains personality
development as progressing through a series of psychosexual stages during childhood. Erikson’s
psychosocial theory suggests that individuals move through eight stages of psychosocial
development across the lifespan, with each stage presenting a unique psychosocial task or crisis.
Behaviorist and social learning theory emphasizes environmental influences on behavior, specifically
classical conditioning and operant conditioning, as well as observational learning. Bandura’s social
learning theory suggests that individuals and the environment interact and influence each other
through reciprocal determinism. Piaget’s cognitive–developmental theory describes cognitive
development as an active process and proceeding through four stages. Information processing
theorists study the steps involved in cognition: perceiving and attending, representing, encoding,
retrieving, and problem-solving. Contextual and systems theories look to the importance of context
in shaping development. Vygotsky’s sociocultural theory emphasizes interactions with members of
our culture in influencing development. Bronfenbrenner’s bioecological model explains
development as a function of the ongoing reciprocal interaction among biological and
psychological changes in the person and his or her changing context. Dynamic systems theory views
children’s developmental capacities, goals, and context as an integrated system that influences the
development of new abilities. Evolutionary developmental psychology integrates Darwinian
principles of evolution and scientific knowledge about the interactive influence of genetic and
environmental mechanisms.
1.4
Describe the methods and research designs used to study human development.
A case study is an in-depth examination of an individual. Interviews and questionnaires are called
self-report measures because they ask the persons under study questions about their own
experiences, attitudes, opinions, beliefs, and behavior. Observational measures are methods that
scientists use to collect and organize information based on watching and monitoring people’s
behavior. Physiological measures gather the body’s physiological responses as data. Scientists use
correlational research to describe relations among measured characteristics, behaviors, and events.
To test hypotheses about causal relationships among variables, scientists employ experimental
research. Developmental designs include cross-sectional research, which compares groups of
people at different ages simultaneously, and longitudinal research, which studies one group of
participants at many points in time. Sequential designs combine the best features of cross-sectional
and longitudinal designs by assessing multiple cohorts over time.
1.5
Discuss principles of research ethics and the ethical issues that may arise in developmental
science research.
Researchers must maximize the benefits to research participants and minimize the harms,
safeguarding participants’ welfare. They must be accurate and honest in their work and respect
participants’ autonomy, including seeking informed consent and child assent. In addition, the
benefits and risks of participation in research must be spread equitably across individuals and
groups. Specific ethical concerns about informed consent, the use of passive consent, and how to
protect participant confidentiality arise in conducting research in lifespan development.
1.6
Describe the field of applied developmental science and the role of intersectionality in
development.
Applied developmental science examines the lifelong interactions among individuals and their
contexts and applies these findings to prevent and intervene in problems and promote positive
development in people of all ages. Individuals’ access to support and opportunity varies
dramatically with race, sex, and other factors. Our unique experiences and perspectives are
influenced by intersectionality, the dynamic interrelations of social categories—gender, race and
ethnicity, sexual orientation, socioeconomic status, immigration status, and disabilities—and the
interwoven systems of power and privilege that accompany social category membership. Central to
intersectionality are the assumptions that all individuals have multiple identities that converge,
within each identity is a dimension of power or oppression, and identities are influenced by the
sociocultural context. Individuals experience multiple overlapping identities and struggle against
intertwined systems of oppression and bias. Intersectionality is inherently tied to context because
the personal importance of social categories and the meaning ascribed to them vary with context.
The study of intersectionality sheds light on how discrimination, marginalization, oppression, and
privilege combine to influence individuals’ experiences in unique ways across the lifespan.
Key Terms
Applied developmental science
Behaviorism
Bioecological systems theory
Case study
Child assent
Chronosystem
Classical conditioning
Cognitive development
Cognitive–developmental theory
Cognitive schemas
Cohort
Computerized tomography (CT scan)
Confidentiality
Context
Continuous change
Correlational research
Cross-sectional research study
Culture
Dependent variable
Development
Developmental science
Diffusion tensor imaging (DTI)
Discontinuous change
Domains of development
Dynamic systems theory
Electroencephalography (EEG)
Emerging adulthood
Ethology
Evolutionary developmental theory
Exosystem
Experimental research
Functional magnetic resonance imaging (fMRI)
Hypotheses
Independent variable
Information processing theory
Informed consent
Intersectionality
Justice
Lifespan human development
Longitudinal research study
Mesosystem
Microsystem
Naturalistic observation
nature–nurture debate
Observational learning
Ontogenetic development
Open-ended interview
Operant conditioning
Passive consent
Physical development
Plasticity
Positron emission tomography (PET scan)
Psychoanalytic theories
Punishment
Questionnaire
Random assignment
Reciprocal determinism
Reinforcement
Resilience
Respect for autonomy
Responsibility
Scientific method
Sequential research design
Social learning theory
Sociocultural theory
Socioemotional development
Structured interview
Structured observation
Theory
Descriptions of Images and Figures
Back to Figure
In the left photo, children are playing a soccer game together and a little girl is running ahead of the
other soccer players, trying to kick the ball in the grassy field. In the middle photo, a school boy is sitting
at desk in a classroom, writing something, and listening with a pleasant face. Behind him are a boy on
the right side and a girl on the left side. In the right side photo two boys with smiling faces are sitting on
steps, talking, and looking at each other.
Back to Figure
Continuous Development shows four stages of life with “Infancy” and “Adulthood” labelled at two ends
with people icons: infant, boy, teenager, adult, from down to top on a semi arch shaped figure.
Discontinuous development shows four stages of life with infancy and adulthood labeled at two ends
with people icons: infant, boy, teenager, adult from down to top in steps.
Back to Figure
The horizontal axis represents age ranges from 0.8 to 2.2, in increments of 0.2. The vertical axis
represents the length (in centimeters) from 58 to 78 in increments of 2. The zig zag line representing the
increases in length as involving a slow and steady process; each month, an infant is taller than the prior
month. The monthly measurements of infant height suggest gradual increases, but daily measurements
show spurts of growth. The graph shows an overall increasing trend.
Back to Figure
In the top figure, a baby is sucking milk from a feeding bottle held in the hand of another person. In the
middle figure a baby is sucking milk from a feeding bottle held in the hand of another person. The index
finger of a hand is touching the forehead of the baby. In the bottom figure, the index finger of a hand is
touching the forehead of the baby.
Back to Figure
It includes “Person”, “Environment”, and “Behavior” and is depicted in the form of a triangle with double
sided arrow pointing to each. On the top left, a text reads “emotional, social, and cognitive abilities” and
on the top right a text reads “knowledge, beliefs, and attitudes” pointing towards “Person”. The text on
the left that points to “Environment” are “physical and social surroundings” and “family and friends”. The
text on the right that points to “Behavior are verbal, motor, and social actions”.
Back to Figure
The inner circle includes “Mesosystem” and “Microsystem”. Under “Mesosystem”, an icon of a teacher
using blackboard is placed; on the left, the text reads as siblings-parents connected with a double arrow
and on the right, students-teachers connected with a double arrow. Below, “Microsystem” is labelled and
an icon of a toddler is placed; on the right, an icon of two toddlers playing and, on the left, an icon of a
nuclear family are placed. Below, the text reads as “Peers-Adults” connected with a double arrow and
“Religious settings” on the left. Below, an icon of a doctor with patient using scanning machine. The texts
read in the side of the inner circle from clockwise are School, Playground, Neighborhood, Home with a
double arrow shows a circle. The second circle includes “Exosystem”; from clockwise: an icon of the
school board with school board labeled, “Local Government”, an icon of the mass media with mass
media labeled, “Religious settings”, Parent’s Workplace, and an icon of a “father, daughter and a dog, a
boy is running” are shown. The outer circle includes “Macrosystem”, from clockwise: an icon of a flag, the
text reads as “customs”, “Government Laws / Policies”, and “Cultural Values”, and an icon of a building
are shown. Below the circular diagram, there is a dotted line with right arrow, the text above the line
reads “Time” at the centre and “CHRONOSYSTEM: Environmental changes and transitions over the
lifespan” on the right.
Back to Figure
Cross sectional data is labelled at the top left above first column and an arrow points towards first
column. There are 4 columns and 5 rows. The first row reads as 2022, 2024, 2026 and 2028. The first,
second, third, and fourth column excluding the first row reads as 12, 14, 16, and 18. The first column and
a diagonal showing 12, 14, 16, 18 are highlighted. An arrow from the highlighted diagonal points to the
text “Longitudinal data”.
2 BIOLOGICAL AND ENVIRONMENTAL FOUNDATIONS
OF DEVELOPMENT
iStock/luismmolina
“Rico and Remmy couldn’t be more different,” marveled their mother. “People are surprised to find out
they are twins.” Rico is tall and athletic, with blond hair and striking blue eyes. He spends most
afternoons playing ball with his friends and often invites them home to play in the yard. Remmy is much
smaller, thin and wiry. He wears thick glasses over his brown eyes that are nearly as dark as his hair.
Unlike his brother, Remmy prefers solitary games and spends most afternoons at home playing video
games, building model cars, and reading comic books. How can Rico and Remmy share the same womb,
have the same parents, and live in the same home yet differ markedly in appearance, personality, and
preferences?
We tend to expect twins like Rico and Remmy to share similarities, as they are often depicted in media
as identical in appearance, personality, and interests. Yet twins tend to differ in many unpredictable ways
despite sharing parents and a home environment. Twins illustrate the complexity of how characteristics
and tendencies are inherited. In this chapter, we discuss the process of genetic inheritance and principles
that can help us to understand how members of a family—even twins—can share a great many
similarities and also many differences.
GENETIC FOUNDATIONS OF DEVELOPMENT
LEARNING OBJECTIVE
2.1 Discuss the genetic foundations of development.
What determines our traits, such as appearance, physical characteristics, health, and personality? We are
born with a hereditary “blueprint” that influences our development. This blueprint is inherited from our
biological parents, as discussed in the following sections.
Genetics
The human body is composed of trillions of units called cells, each with a nucleus containing 23
matching pairs of rod-shaped structures called chromosomes (Finegold, 2019). Each chromosome holds
the basic units of heredity, known as genes, composed of stretches of deoxyribonucleic acid (DNA), a
complex molecule shaped like a twisted ladder or staircase. Genes carry the plan for creating all of the
traits that organisms carry. It is estimated that 20,000 to 25,000 genes reside within the chromosomes,
comprising the human genome and influencing all genetic characteristics (Taneri et al., 2020).
Much of our genetic material is not unique to humans. Every species has a different genome, yet we
share some genes with all organisms, from bacteria to primates. We share nearly 99% of our DNA with
our closest genetic relative, the chimpanzee. There is even less genetic variation among humans. People
around the world share 99.9% of their genes (Lewis, 2017; National Human Genome Research Institute,
2018). Although all humans share the same basic genome, every person has a slightly different code,
making them genetically distinct from other humans.
Cell Reproduction
Most cells in the human body reproduce through a process known as mitosis, in which DNA replicates
itself, duplicating chromosomes, resulting in new cells with identical genetic material (Sadler, 2018). The
process of mitosis accounts for the replication of body cells. Sex cells reproduce in a different way,
through meiosis. First, the 46 chromosomes begin to replicate as in mitosis, duplicating themselves. But
before the cell completes dividing, a critical process called
takes place. The chromosome
pairs align and DNA segments cross over, moving from one member of the pair to the other, essentially
“mixing up” the DNA. Crossing over thereby creates unique combinations of genes (Finegold, 2019). The
resulting cell consists of only 23 single, unpaired chromosomes. Known as gametes, these cells are
specialized for sexual reproduction: sperm in males and ova in females. Ova and sperm join at
fertilization to produce a fertilized egg, or zygote, with 46 chromosomes, forming 23 pairs with half from
the biological mother and half from the biological father. Each gamete has a unique genetic profile, and
it is estimated that individuals can produce millions of genetically different gametes (U.S. National
Library of Medicine, 2020).
crossing over
Sex Determination
The sex chromosomes determine whether a zygote will develop into a male or female. Twenty-two of the
23 pairs of chromosomes are matched pairs (Figure 2.1). They contain similar genes in almost identical
positions and sequence, reflecting the distinct genetic blueprint of the biological mother and father. The
23rd pair of chromosomes are not identical because they are sex chromosomes that specify the genetic
sex of the individual. In females, sex chromosomes consist of two large X-shaped chromosomes (XX).
Males’ sex chromosomes consist of one large X-shaped chromosome and one much smaller Y-shaped
chromosome (XY).
Description
Figure 2.1 Chromosomes
Source: iStock/somersault18:24
Because females have two X sex chromosomes, all their ova contain one X sex chromosome. A male’s
sex chromosome pair includes both X and Y chromosomes; therefore, one half of the sperm males
produce contain an X chromosome and one half contain a Y. The Y chromosome contains genetic
instructions that will cause the fetus to develop male reproductive organs. Thus, whether the fetus
develops into a boy or girl is determined by which sperm fertilizes the ovum. If the ovum is fertilized by
a Y sperm, a male fetus will develop, and if the ovum is fertilized by an X sperm, a female fetus will form
(Figure 2.2).
Description
Figure 2.2 Sex Determination
Genes Shared by Twins
All biological siblings share the same parents, inheriting chromosomes from each. Despite this genetic
similarity, siblings are often quite different from one another. Twins are siblings who share the same
womb. Twins occur in about 1 out of every 33 births in the United States (Martin et al., 2018).
The majority of naturally conceived twins (over 70%) are dizygotic (DZ) twins, or fraternal twins,
conceived when a woman releases more than one ovum and each is fertilized by a different sperm (Gill
et al., 2019). DZ twins share about one half of their genes and, like other siblings, most fraternal twins
differ in appearance, such as hair color, eye color, and height. In about half of fraternal twin pairs, one
twin is a boy and the other a girl. DZ twins tend to run in families, suggesting a genetic component that
controls the tendency for a woman to release more than one ovum each month (Hazel et al., 2020).
Rates of DZ twins also increase with in vitro fertilization, maternal age, and with each subsequent birth
(Gill et al., 2019; Pison et al., 2015).
Monozygotic (MZ) twins, or identical twins, originate from the same zygote, sharing the same
genotype, or set of genetic instructions for all physical and psychological characteristics. MZ twins occur
when the zygote splits into two distinct separate but identical zygotes that develop into two infants. It is
estimated that MZ twins occur in 1 in every 250 births (American College of Obstetricians and
Gynecologists, & Society for Maternal-Fetal Medicine, 2014). The causes of MZ twinning are not well
understood (McNamara et al., 2016). Rates of MZ twins are not related to maternal age or the number of
births, but in vitro fertilization, discussed later, appears to increase the odds of MZ twins (Busnelli et al.,
2019; Knopman et al., 2014). DZ twins have become more common in recent decades with advances in
reproductive technology, such as in vitro fertilization (Chapter 3) (Rhea et al., 2017).
Monozygotic, or identical, twins share 100% of their DNA.
Ray Evans/Alamy Stock Photo
Patterns of Genetic Inheritance
Although the differences among various members of a given family may appear haphazard, they are the
result of a genetic blueprint unfolding. Researchers are just beginning to uncover the instructions
contained in the human genome, but we have learned that traits and characteristics are inherited in
predictable ways.
Dominant–Recessive Inheritance
Lynn has red hair while her brother, Jim, does not—and neither do their parents. How did Lynn end up
with red hair? These outcomes can be explained by patterns of genetic inheritance, how the sets of
genes from each parent interact. As we have discussed, each person has 23 pairs of chromosomes, one
pair inherited from the mother and one from the father. The genes within each chromosome can be
expressed in different forms, or alleles, that influence a variety of physical characteristics.
When alleles of the pair of chromosomes are alike with regard to a specific characteristic, such as hair
color, the person is said to be homozygous for the characteristic and will display the inherited trait. If
they are different, the person is heterozygous, and the trait expressed will depend on the relations
among the genes (Plomin, 2019). Some genes are passed through dominant–recessive inheritance in
which some genes are dominant and are always expressed regardless of the gene they are paired with.
Non-red hair is a dominant gene. Other genes, such as for red hair, are recessive and will be expressed
only if paired with another recessive gene. Lynn and Jim’s parents are heterozygous for red hair; both
have dark hair, but they each carry a recessive gene for red hair.
When an individual is heterozygous for a particular trait, only the dominant gene is expressed, and the
person becomes a carrier of the recessive gene. Both parents have non-red hair but may have
homozygous or heterozygous genes for hair color because the gene for non-red hair (symbolized by N
in Figure 2.3) is dominant over the gene for red hair (r). If both parents are heterozygous for red hair
(Nr), children who inherit a homozygous pair of dominant genes (NN) and others who inherit a
heterozygous pair (Nr) will have non-red hair, even though the two genotypes are different. Those who
inherit a heterozygous pair (NR) carry the gene for red hair and can pass it on to their offspring. Red hair
can result only from having two recessive genes (rr), which means that both parents must carry the
recessive gene for red hair, even if they display non-red hair.
Description
Figure 2.3 Dominant–Recessive Inheritance
Several characteristics are passed through dominant–recessive inheritance (Table 2.1).
Table 2.1 Dominant and Recessive Characteristics
Dominant Trait
Dark hair
Curly hair
Hair
Non-red hair
Facial dimples
Recessive Trait
Blond hair
Straight hair
Baldness
Red hair
No dimples
Dominant Trait
Brown eyes
Second toe longer than big toe
Type A blood
Type B blood
Rh-positive blood
Normal color vision
Recessive Trait
Blue, green, hazel eyes
Big toe longer than second toe
Type O blood
Type O blood
Rh-negative blood
Color blindness
Source: McKusick-Nathans Institute of Genetic Medicine (2020).
Incomplete Dominance
In most cases, dominant–recessive inheritance is an oversimplified explanation for patterns of genetic
inheritance. Incomplete dominance is a genetic inheritance pattern in which both genes jointly
influence the characteristic (Knopik et al., 2017). Consider blood type. Neither the alleles for blood type
A and B dominate each other. A heterozygous person with the alleles for blood type A and B will express
both A and B alleles and have blood type AB.
A different type of inheritance pattern is seen when a person inherits heterozygous alleles in which one
allele is stronger than the other yet does not completely dominate. In this situation, the stronger allele
does not mask all of the effects of the weaker allele. Therefore some, but not all, characteristics of the
recessive allele appear. The trait for developing normal blood cells does not completely mask the allele
for developing sickle-shaped blood cells. About 5% of African American newborns (and relatively few
Caucasians or Asian Americans) carry the recessive sickle cell trait (Ojodu et al., 2014). Individuals who
are homozygous for the recessive sickle cell trait develop sickle cell anemia, a disorder in which sickle
cell alleles cause red blood cells to become crescent, or sickle, shaped. Cells that are sickle-shaped
cannot distribute oxygen effectively throughout the circulatory system and can cause inflammation and
damage the blood vessels (Ware et al., 2017). The life expectancy for individuals with sickle cell anemia is
55 years in North America (Pecker & Little, 2018). Alleles for normal blood cells do not mask all of the
characteristics of recessive sickle cell alleles, illustrating incomplete dominance. People who carry a
single recessive sickle cell gene do not develop full-blown sickle cell anemia (Chakravorty & Williams,
2015). Carriers of the trait for sickle cell anemia tend to function normally but may show some
symptoms, such as reduced oxygen distribution throughout the body and exhaustion after exercise (Xu
& Thein, 2019).
Recessive sickle cell alleles cause red blood cells to become crescent-shaped
and unable to distribute oxygen effectively throughout the circulatory
system. Alleles for normal blood cells do not mask all of the characteristics of
recessive sickle cell alleles, illustrating incomplete dominance.
BSIP SA/Alamy Stock Photo
Polygenic Inheritance
Whereas dominant–recessive and incomplete dominance patterns account for some genotypes, most
traits are a function of the interaction of many genes, known as polygenic inheritance. Hereditary
influences act in complex ways, and researchers cannot trace most characteristics to only one or two
genes, but rather, the result of interactions among many genes (Armstrong-Carter et al., 2021). Examples
of polygenic traits include height, intelligence, personality, and susceptibility to certain forms of cancer
(Bouchard, 2014; Flint et al., 2020; Penke & Jokela, 2016). As the number of genes that contribute to a
trait increases, so does the range of possible traits. Genetic propensities interact with environmental
influences to produce a wide range of individual differences in human traits.
Genomic Imprinting
The principles of dominant–recessive and incomplete dominance inheritance can account for over 1,000
human traits (Finegold, 2019). A few traits are determined by a process known as genomic imprinting.
Genomic imprinting refers to the instance in which the expression of a gene is determined by whether it
is inherited from the mother or the father (Kelly & Spencer, 2017; Thamban et al., 2020). Consider two
conditions that illustrate genomic imprinting: Prader-Willi syndrome and Angelman syndrome. Both
syndromes are caused by an abnormality in the 15th chromosome (Kalsner & Chamberlain, 2015). If the
individual acquires the chromosome 15 abnormality from the biological father, the individual, whether a
daughter or son, will develop Prader-Willi syndrome (Figure 2.4), a set of specific physical and behavioral
characteristics including obesity, insatiable hunger, short stature, motor slowness, and mild to moderate
developmental delays (Butler et al., 2016).
Description
Figure 2.4 Genomic Imprinting
Source: Adapted from C. Cristofre Martin (1998).
If the abnormal chromosome 15 arises from the mother, the individual—again, whether it is a daughter
or a son—will develop Angelman syndrome, characterized by hyperactivity, thin body frame, seizures,
disturbances in gait, severe developmental delay or intellectual disability, and speech impairment
(Buiting et al., 2016; Dagli & Williams, 2017). Prader-Willi and Angelman syndromes are rare, occurring
on average in 1 in 12,000 to 20,000 persons (Kalsner & Chamberlain, 2015; Spruyt et al., 2018). Patterns
of genetic inheritance can be complex, yet they follow predictable principles (Table 2.2).
Table 2.2 Summary: Patterns of Genetic Inheritance
Inheritance
Pattern
Dominant–
recessive
inheritance
Incomplete
dominance
Polygenic
inheritance
Genomic
imprinting
Description
Genes that are dominant are always expressed, regardless of the gene they are
paired with. Recessive genes are expressed only if paired with another recessive
gene.
Both genes influence the characteristic, and aspects of both genes appear.
Polygenic traits are the result of interactions among many genes.
The expression of a gene is determined by whether it is inherited from the mother or
the father.
Thinking in Context: Biological Influences
1. From an evolutionary developmental perspective (Chapter 1), why might twins occur? Does
twinning serve an adaptive purpose for our species? Why or why not?
2. Consider your own physical characteristics, such as hair and eye color. Are they indicative of
recessive traits or dominant ones?
3. Do you think that you might be a carrier of recessive traits? Why or why not?
CHROMOSOMAL AND GENETIC PROBLEMS
LEARNING OBJECTIVE
2.2 Identify examples of genetic disorders and chromosomal abnormalities.
Many disorders are passed through genetic inheritance, the result of chromosomal abnormalities.
Hereditary and chromosomal abnormalities can often be diagnosed prenatally. Others are evident at
birth or can be detected soon after an infant begins to develop. Some are discovered only over a period
of many years.
Genetic Disorders
Disorders and abnormalities that are inherited through the parents’ genes are passed through the
inheritance processes that we have discussed. These include well-known conditions as sickle cell anemia,
as well as others that are rare. Some are highly visible and others go unnoticed throughout an
individual’s life.
Dominant–Recessive Disorders
Recall that in dominant–recessive inheritance, dominant genes are always expressed regardless of the
gene they are paired with and recessive genes are expressed only if paired with another recessive gene.
Some diseases are inherited through dominant–recessive patterns (Table 2.3). Few severe disorders are
inherited through dominant inheritance because individuals who inherit the allele often do not survive
long enough to reproduce and pass it to the next generation. One exception is Huntington disease, a
fatal disease in which the central nervous system deteriorates (Ghosh & Tabrizi, 2018; McKusick-Nathans
Institute of Genetic Medicine, 2020). Individuals with the Huntington allele develop normally in
childhood, adolescence, and young adulthood. Symptoms of Huntington disease do not appear until
age 35 or later. By then, many individuals have already had children, and one half of them, on average,
will inherit the dominant Huntington gene.
Table 2.3 Diseases Inherited Through Dominant–Recessive Inheritance
Disease
Occurrence
Huntington
disease
1 in 20,000
Mode of
Inheritance Description
Dominant Degenerative brain disorder that
affects muscular coordination and
cognition
Cystic fibrosis
1 in 2,000–2,500
Recessive
Phenylketonuria 1 in 10,000–
(PKU)
15,000
Recessive
Treatment
No cure; death
usually occurs
10 to 20 years
after onset
An abnormally thick, sticky mucus Bronchial
clogs the lungs and digestive
drainage, diet,
system, leading to respiratory
gene
infections and digestive difficulty replacement
therapy
Inability to digest phenylalanine
Diet
that, if untreated, results in
neurological damage and death
Disease
Occurrence
Sickle cell
anemia
1 in 500 African
Americans
Mode of
Inheritance Description
Recessive
Sickling of red blood cells leads
to inefficient distribution of
oxygen throughout the body that
leads to organ damage and
respiratory infections
Treatment
No cure; blood
transfusions,
treat infections,
bone marrow
transplant;
death by
middle age
Tay-Sachs
disease
1 in 3,600 to
4,000
descendants of
Central and
Eastern European
Jews
Recessive
Degenerative brain disease
None; most die
by 4 years of
age
Source: McKusick-Nathans Institute of Genetic Medicine (2020).
Phenylketonuria (PKU) is a common recessive disorder that prevents the body from producing an
enzyme that breaks down phenylalanine, an amino acid, from proteins (McKusick-Nathans Institute of
Genetic Medicine, 2020). Without treatment, the phenylalanine builds up quickly to toxic levels that
damage the central nervous system, contributing to intellectual developmental disability, once known as
mental retardation, by 1 year of age. The United States and Canada require all newborns to be screened
for PKU (Camp et al., 2014).
A blood sample to detect PKU is taken from this newborn. Phenylketonuria
(PKU) is a genetic disorder in which the body lacks the enzyme that breaks
down phenylalanine. Without treatment, the phenylalanine builds up to toxic
levels and can damage the central nervous system.
Marmaduke St. John/Alamy Stock Photo
PKU illustrates how genes interact with the environment to produce developmental outcomes.
Intellectual disability results from the interaction of the genetic predisposition and exposure to
phenylalanine from the environment (Blau, 2016). Children with PKU can process only very small
p
y
(
,
)
p
y
y
amounts of phenylalanine. If the disease is discovered, the infant is placed on a diet low in
phenylalanine. Yet, it is very difficult to remove nearly all phenylalanine from the diet. Individuals who
maintain a strict diet usually attain average levels of intelligence, though they tend to score lower than
those without PKU (Hofman et al., 2018; Romani et al., 2017). Some cognitive and psychological
problems may appear in childhood and persist into adulthood, particularly difficulty in attention and
planning skills, emotional regulation, depression, and anxiety (Christ et al., 2020; Erlich, 2019; Ford et al.,
2018; Hawks et al., 2018; Jahja et al., 2017). The emotional and social challenges associated with PKU,
such as the pressure of a strict diet and surveillance from parents, may worsen these symptoms and
dietary compliance tends to decline in adolescence when young people push boundaries and seek
independence (Medford et al., 2017).
X-Linked Disorders
A special instance of the dominant–recessive pattern occurs with genes that are located on the X
chromosome (Shah et al., 2017). Recall that males (XY) have both an X and a Y chromosome. Some
recessive genetic disorders, like the gene for red-green colorblindness, are carried on the X chromosome
(Table 2.4). Males are more likely to be affected by X-linked genetic disorders because they have only
one X chromosome and therefore any genetic marks on their X chromosome are displayed. Females (XX)
have two X chromosomes; a recessive gene located on one X chromosome will be masked by a
dominant gene on the other X chromosome. Females are thereby less likely to display X-linked genetic
disorders because both of their X chromosomes must carry the recessive genetic disorder for it to be
displayed.
Fragile X syndrome is an example of a dominant–recessive disorder carried on the X chromosome
(Hagerman et al., 2017; Salcedo-Arellano et al., 2020). Because the gene is dominant, it needs to appear
on only one X chromosome to be displayed. That means that fragile X syndrome occurs in both males
and females. Males with fragile X syndrome typically have a long, narrow face; large ears; and large
testes. Fragile X syndrome (FXS) is the most commonly known inherited form of intellectual disability (ID)
(Doherty & Scerif, 2017), and children with fragile X syndrome tend to show moderate to severe
intellectual disability and problems with executive function (Raspa et al., 2017; Schmitt et al., 2019).
Cardiac defects are common as well as several behavioral mannerisms, including poor eye contact and
repetitive behaviors such as hand flapping, hand biting, and mimicking others, behaviors common in
individuals with autism spectrum disorders (Hagerman et al., 2017; Salcedo-Arellano et al., 2020). Fragile
X syndrome is often codiagnosed with autism with estimates of about 40–60% of boys and 16–20% of
girls with fragile X syndrome meeting the diagnostic criteria for autism (Bagni & Zukin, 2019; Kaufmann
et al., 2017). As carriers, females may show some characteristics of the disorder but tend to display levels
of intelligence within the normal or near-normal range.
Hemophilia, a condition in which the blood does not clot normally, is another example of a recessive
disease inherited through genes on the X chromosome (McKusick-Nathans Institute of Genetic
Medicine, 2020; Shah et al., 2017). Daughters who inherit the gene for hemophilia typically do not show
the disorder because the gene on their second X chromosome promotes normal blood clotting and is a
dominant gene (d’Oiron, 2019). Females, therefore, can carry the gene for hemophilia without exhibiting
the disorder. A female carrier has a 50/50 chance of transmitting the gene to each child. Sons who
inherit the gene will display the disorder because the Y chromosome does not have the corresponding
genetic information to counter the gene. Daughters who inherit the gene, again, will be carriers (unless
their second X chromosome also carries the gene).
Table 2.4 Diseases Acquired Through X-Linked Inheritance
Syndrome/Disease Occurrence Description
Color blindness
1 in 12
Difficulty distinguishing red from green; less
males
common is difficulty distinguishing blue from
green
Duchenne
1 in 3,500
Weakness and wasting of limb and trunk
muscular
males
muscles; progresses slowly but will affect all
dystrophy
voluntary muscles
Fragile X syndrome 1 in 4,000
males and
1 in 8,000
females
Hemophilia
1 in 3,000–
7,000
males
Symptoms include cognitive impairment,
attention problems, anxiety, unstable mood,
long face, large ears, flat feet, and
hyperextensible joints, especially fingers
Blood disorder in which the blood does not
clot
Treatment
No cure
Physical therapy,
exercise, body
braces; survival
rare beyond late
20s
No cure
Blood transfusions
Source: McKusick-Nathans Institute of Genetic Medicine (2017).
Chromosomal Abnormalities
Chromosomal abnormalities are the result of errors during cell reproduction, meiosis or mitosis, or
damage caused afterward. Occurring in about 1 of every 1,500 births, the most widely known
chromosome disorder is trisomy 21, more commonly called Down syndrome (de Graaf et al., 2017;
McKusick-Nathans Institute of Genetic Medicine, 2020). Down syndrome occurs when a third
chromosome appears alongside the 21st pair of chromosomes. Down syndrome is associated with
marked physical, health, and cognitive attributes, including a short, stocky build, and often a round face,
almond-shaped eyes, and a flattened nose (Antonarakis et al., 2020; Bull, 2020). Children with Down
syndrome tend to show delays in physical and motor development relative to other children, and health
problems, such as congenital heart defects, vision impairments, poor hearing, and immune system
deficiencies (Diamandopoulos & Green, 2018; Morrison & McMahon, 2018; Roizen et al., 2014; Zampieri
et al., 2014).
Down syndrome is the most common cause of intellectual disability.
Interventions that encourage children to interact with their physical and
social environment can promote motor, social, and emotional development.
iStock/mediaphotos
Down syndrome is the most common genetic cause of intellectual developmental disability (Vissers et
al., 2016), but children’s abilities vary. Generally, individuals with Down syndrome show greater strengths
in nonverbal learning and memory relative to their verbal skills (Grieco et al., 2015). Expressive language
is delayed relative to comprehension. Infants and children who participate in early intervention and
receive sensitive caregiving and encouragement to explore their environment show positive outcomes,
especially in the motor, social, and emotion areas of functioning (Bull, 2020; Næss et al., 2017; Wentz,
2017).
Advances in medicine have addressed many of the physical health problems associated with Down
syndrome, so that today the average life expectancy is 60 years of age, as compared with about 25 in
the 1980s (Glasson et al., 2014; National Association for Down Syndrome, 2020). Many individuals live
into their 70s and 80s. However, Down syndrome is associated with premature aging and an accelerated
decline of cognitive functioning (Covelli et al., 2016; Ghezzo et al., 2014; Hithersay et al., 2017).
Individuals with Down syndrome are at risk to show signs of Alzheimer’s disease very early relative to
other adults (Antonarakis et al., 2020; Tramutola et al., 2020). This is an example of how disorders and
illnesses can be influenced by multiple genes and complex contextual interactions; in this case, Down
syndrome and Alzheimer’s disease share genetic markers (Handen, 2020; Lee et al., 2017).
Some chromosomal abnormalities concern the 23rd pair of chromosomes: the sex chromosomes. These
abnormalities result from either an additional or missing sex chromosome. Given their different genetic
makeup, sex chromosome abnormalities yield different effects in males and females (Table 2.5)
One of the most common sex chromosome abnormalities, with prevalence estimates between 1 in 500
and 1 in 1,000 males, is Klinefelter syndrome, in which males are born with an extra X chromosome
(XXY) (McKusick-Nathans Institute of Genetic Medicine, 2020; Wistuba et al., 2017). Symptoms range in
severity such that some males experience symptoms that impair daily life, but most may be unaware of
the disorder until they are tested for infertility (Bird & Hurren, 2016; Gravholt et al., 2018). Severe
symptoms include a high-pitched voice, feminine body shape, breast enlargement, and infertility. Many
boys and men with Klinefelter syndrome have short stature, a tendency to be overweight, and language
and short-term memory impairments that can cause difficulties in learning (Bonomi et al., 2017). As
adults, men with Klinefelter syndrome are at risk for a variety of disorders that are more common in
women, such as osteoporosis (Juul et al., 2011).
A second type of sex chromosome abnormality experienced by men is XYY syndrome, or Jacob’s
syndrome, a condition that causes men to produce high levels of testosterone (McKusick-Nathans
Institute of Genetic Medicine, 2017; Pappas et al., 2017). In adolescence, they tend to be slender and
show severe acne and poor coordination, but most men with XYY syndrome are unaware that they have
a chromosomal abnormality. The prevalence of XYY syndrome is uncertain given that most men go
undiagnosed. Females are susceptible to a different set of sex chromosome abnormalities. About 1 in
1,000 females are born with three X chromosomes, known as triple X syndrome (McKusick-Nathans
Institute of Genetic Medicine, 2020; Wigby et al., 2016). Women with triple X syndrome show an
appearance within the norm. They tend to be about an inch or so taller than average, with unusually
long legs and slender torsos, as well as normal development of sexual characteristics and fertility. Some
may score lower on inteligence tests or have learning difficulties. Because many cases of triple X
syndrome often go unnoticed, little is known about the syndrome.
The sex chromosome abnormality known as Turner syndrome occurs when a female is born with only
one X chromosome (McKusick-Nathans Institute of Genetic Medicine, 2020). Girls with Turner syndrome
show abnormal growth patterns. They show delayed puberty, their ovaries do not develop normally, they
do not ovulate, and they are infertile (Culen et al., 2017; Davis et al., 2020). As adults, they are short in
stature and often have small jaws with extra folds of skin around their necks (webbing) and lack
prominent female secondary sex characteristics such as breasts (Gravholt et al., 2019). Malformations of
the heart, diabetes, autoimmune disorders, and early osteoporosis are common (Gravholt et al., 2019).
Children with Turner syndrome may show difficulty with visual-spatial reasoning and memory, attention,
executive functioning, and motor and math skills (Hutaff-Lee et al., 2019). They are also prone to social
difficulties, anxiety, and depression (Christopoulos et al., 2008; Powell & Schulte, 2011). Current
estimates put its frequency at 1 in 2,500 worldwide (National Library of Medicine, 2019). If Turner
syndrome is diagnosed early, regular injections of human growth hormones can increase stature, and
hormones administered at puberty can result in some breast development and menstruation (Culen et
al., 2017; Klein et al., 2020).
Table 2.5 Sex Chromosome Abnormalities
Female
Genotype Syndrome Description
XO
Turner
Abnormal growth patterns, delayed puberty, lack prominent
female secondary sex characteristics, and infertility. Short adult
stature, webbing around their neck.
XXX
Triple X
Grow about an inch or so taller than average with unusually long
legs and slender torsos, and show normal development of sexual
characteristics and fertility. Because many cases of triple X
syndrome often go unnoticed, little is known about the
syndrome.
Male
Syndrome Description
Genotype
Prevalence
1 in 2,500
females
Unknown;
many
cases go
unnoticed
Prevalence
Female
Genotype Syndrome Description
XXY
Klinefelter High-pitched voice, short stature, feminine body shape, and
infertility. Increased risk for osteoporosis and other disorders that
are more common in women.
XYY
Jacob’s
Accompanied by high levels of testosterone.
syndrome
Prevalence
1 in 1,000
males
Unknown;
many
cases go
unnoticed
Mutation
Not all inborn characteristics are inherited. Some result from mutations, sudden changes and
abnormalities in the structure of genes that occur spontaneously or may be induced by exposure to
environmental toxins such as radiation and agricultural chemicals in food. A mutation may involve only
one gene or many. It is estimated that as many as one half of all conceptions include mutated
chromosomes (Taneri et al., 2020). Most mutations are fatal—the developing organism often dies very
soon after conception, often before the woman knows she is pregnant (Sadler, 2018).
Sometimes mutations are beneficial. This is especially true if the mutation is induced by stressors in the
environment and provides an adaptive advantage to the individual. The sickle cell gene (discussed earlier
in this chapter) is a mutation that originated in areas where malaria is widespread, such as Africa (Ware
et al., 2017), and serves a protective role against malaria (Uyoga et al., 2019).
Children who inherited a single sickle cell allele were more resistant to malarial infection and more likely
to survive and pass it along to their offspring (Croke et al., 2017; Gong et al., 2013). The sickle cell gene
is not helpful in places where malaria is not a risk. The frequency of the gene is decreasing in areas of
the world where malaria is uncommon. Only 8% of African Americans are carriers, compared with as
many as 30% of Black Africans in some African countries (Maakaron et al., 2012). Therefore, the
developmental implications of genotypes—and mutations—are context specific, posing benefits in
some contexts and risks in others.
Thinking in Context: Biological Influences
Recall from Chapter 1 that most developmental scientists agree that nature and nuture interact to
influence development. Choose a genetic or chromosomal disorder discussed in this section and explain
how it illustrates the interaction of genes and context.
Thinking in Context: Lifespan Development
Chromosomal and genetic problems can result in a variety of impairments. How might contextual
factors, such as a supportive environment, aid individuals’ development? Describe a specific problem or
mutation. What environmental conditions might best promote healthy adjustment for individuals with
this disorder?
REPRODUCTIVE CHOICES: GENETIC COUNSELING ASSISTED
REPRODUCTIVE TECHNOLOGY
LEARNING OBJECTIVE
2.3 Explain the choices of reproductive technology available to individuals and couples who wish to
conceive by alternative means.
The likelihood of genetic disorders often can be predicted before conception. Our growing
understanding of genetic inheritance has led many couples to consider their own genetic inheritance
and what genes they will pass on to their children. Advances in technology permit abnormalities to be
detected, and sometimes treated, earlier than ever before.
Genetic Counseling
The popularity of DNA tests has provided many people with information about their genetic makeup.
Many prospective parents seek genetic counseling to determine the risk that their children will inherit
genetic defects and chromosomal abnormalities (Ioannides, 2017). Candidates for genetic counseling
include those whose relatives have a genetic condition, couples who have had difficulties bearing
children, women over the age of 35, and couples from the same ethnic group. Genetic testing can also
determine whether a couple’s difficulties conceiving or recurrent miscarriages are influenced by
chromosomal abnormalities in the male’s sperm (Kohn et al., 2016; Softness et al., 2020).
Parents meet with a genetic counselor to determine the risk that their
children will inherit genetic defects and chromosomal abnormalities.
Michelle Del Guercio/Science Source
The genetic counselor interviews the couple to construct a family history of heritable disorders for both
prospective biological parents. This service is particularly valuable when one or both prospective parents
have relatives with inborn disorders. If a disorder is common in either parent’s family or it appears that
they are likely to carry a genetic disorder, genetic screening blood tests may be carried out on both
parents to detect the presence of dominant and recessive genes and chromosomal abnormalities
associated with various disorders. The tests determine whether each parent is a carrier for recessive
disorders, such as Huntington disease, and estimate the likelihood that a child may be affected by a
genetic disorder (Nance, 2017). The genetic counselor interprets the results and helps the parents
understand genetic concepts by tailoring the explanation to match the parents’ knowledge (Abacan et
al., 2019).
Once prospective parents learn about the risk of conceiving a child with a disorder, they can determine
how to proceed—whether it is to conceive a child naturally or through the use of in vitro fertilization
after screening gametes for the disorders of concern. Given advances in our knowledge of genetic
disorders and ability to screen for them, some experts propose that genetic counseling should be
available to all prospective parents (Minkoff & Berkowitz, 2014). Others argue that abnormalities are rare
and so few would be discovered that universal screening is of little utility (Larion et al., 2016). Whether to
seek genetic counseling is a personal decision for prospective parents based on their history, view of
their risks, and their values. Adults who carry significant risks of conceiving a child with a genetic
disorder sometimes consider alternative methods of reproduction.
Assisted Reproductive Technology
Couples turn to assisted reproductive technology (ART), alternative methods of conception that rely on
medical technology, for a variety of reasons. Almost 2% of infants in the United States are conceived
through ART (Centers for Disease Control and Prevention, 2020). As noted, some couples at risk for
bearing children with genetic or chromosomal abnormalities seek ART. About 15% of couples in the
United States experience infertility, the inability to conceive naturally after 1 year of unprotected
intercourse (Anwar & Anwar, 2016; Lindahl, 2018). About 35% of the time, factors within the male are
identified as contributors to infertility (Centers for Disease Control and Prevention, 2017). In addition,
single men and women, as well as gay and lesbian couples, often opt to conceive with the use of ART.
There are racial, ethnic, and socioeconomic disparities in the use of ART. White, Asian American, collegeeducated, and high socioeconomic status women are more likely to give birth with ART than Black and
Hispanic women (Janitz et al., 2016; Tierney & Cai, 2019). Race and ethnicity are often linked with
socioeconomic status and disparities in health care in the United States. Socioeconomic factors play a
large role in access to infertility treatment and reproductive technology (Dieke et al., 2017).
Artificial Insemination
The simplest, least invasive type of alternative conception is artificial insemination, the injection of
sperm into a woman. The male partner’s sperm may be used or, if the male experiences reproductive
difficulties, a donor’s sperm may be used. Artificial insemination through a donor also enables women
without male partners, whether single or lesbian, to conceive. Artificial insemination is the least
expensive alternative method of conception, but the success rate is low, usually requiring multiple cycles.
The injection costs range from about $300 to $1,000 per cycle (Harris, 2020). Women and couples who
seek donor sperm may also expect to pay about $700 to $1,000 per vial.
In Vitro Fertilization
In contrast with artificial insemination, where conception occurs inside of the women’s body, in vitro
fertilization, introduced in the United States in 1981, initiates conception outside of the woman’s body. A
woman is prescribed hormones that stimulate the maturation of several ova, which are surgically
removed. The ova are placed in a dish and sperm are added. One or more ova are fertilized and the
resulting cell begins to divide. After several cell divisions, the cluster of cells is placed in the woman’s
uterus. If they implant into the uterus and begin to divide, a pregnancy has occurred.
In vitro fertilization is a form of reproductive technology in which an ovum is
fertilized outside of the womb.
Mauro Fermariello/Science Source
The success rate of in vitro fertilization is about 50% and varies with the mother’s age (Centers for
Disease Control and Prevention, 2019). For example, the percentage of embryo transfers resulting in live
births is 53% for 35- to 37-year-old women, 36% in 38–40-year-old women, 25% in 41–42-year-old
women, and 11% in women over age 43. In vitro fertilization is expensive, costing an average of over
$12,400 per trial, not including medication, and often requires multiple cycles, posing a financial burden
too great for low SES women and couples (Asch & Marmor, 2020; Teoh & Maheshwari, 2014).
Infants conceived by in vitro fertilization are at higher risk of low birth weight (Centers for Disease
Control and Prevention, 2019), although it has been suggested that it is because of maternal factors
such as advanced age and health, and not in vitro fertilization per se (Seggers et al., 2016). Infants
conceived by in vitro fertilization show no differences in growth, health, development, and cognitive
function relative to infants conceived naturally (Farhi et al., 2019; Fauser et al., 2014). Because in vitro
fertilization permits cells to be screened for genetic problems prior to implantation, in vitro infants are
not at higher risk of birth defects (Fauser et al., 2014). More than one-third of births from artificial
insemination included more than one infant (Sunderam et al., 2019). Multiple gestations increase the risk
for low birth weight, prematurity, and other poor outcomes (Sullivan-Pyke et al., 2017).
Surrogacy
Surrogacy is an alternative form of reproduction; a woman (the surrogate) is impregnated and carries a
fetus to term and agrees to turn the baby over to a woman, man, or couple who will raise it. Single
parents, same-sex couples, and couples in which one or both members are infertile may choose
surrogacy. Sometimes the surrogate carries a zygote composed of one or both of the couple’s gametes.
Other times, the ova, sperm, or zygote are donated. Despite several highly publicized cases of surrogate
mothers deciding not to relinquish the infant, most surrogacies are successful.
In 2015, 2,807 babies were born through surrogacy in the United States, up from 738 in 2004, according
to the American Society for Reproductive Medicine (Beitsch, 2017). Longitudinal research suggests no
psychological differences through age 14 between children born through surrogacy compared with
other methods, including children born to gay father and lesbian mother families (Carone et al., 2018,
2020; Golombok, 2013; Golombok et al., 2017). In addition, mothers of children who were the product of
surrogates do not differ from those conceived using other methods and surrogate mothers show no
negative effects (Jadva et al., 2015; Söderström-Anttila et al., 2015).
We have seen that reproductive technology is expensive. Surrogacy is often prohibitively expensive for
most prospective parents, limiting its access to high socioeconomic status parents. Prospective parents
pay for the surrogate’s medical care, attorney, travel expenses, health care, and more, which can amount
to $100,000 or more (Caron, 2020). Finally, surrogacy may pose ethical issues. Carrying a fetus to term
poses physical and mental health risks to the surrogate. Relinquishing a newborn is difficult, even with
fore planning, posing emotional risks to the surrogate. The financial incentives to surrogate a fetus are
substantial. Women are often paid at least $30,000 to $55,000 to surrogate a fetus (Beitsch, 2017), sums
that may be difficult for low socioeconomic status women to resist (Harrison, 2017).
Assisted Reproductive Technology and Sex Selection
Gender-reveal parties, in which prospective parents learn about and share the biological sex of their
fetus by popping balloons, breaking apart piñatas, lighting fireworks, and other creative means, are
popular and signify the relevance of biological sex for many parents. Parents have long shown a
preference for giving birth to a girl or boy, depending on circumstances such as cultural or religious
traditions, the availability of men or women to perform certain kinds of work important to the family or
society, or the sex of the couple’s other children. Today, many parents cannot only know their child’s sex
but might choose it. The introduction of sex selection has been a boon to couples carrying a genetically
transmitted disease (i.e., a disease carried on the sex chromosomes), enabling them to have a healthy
baby of the sex unaffected by the disease they carry.
There are two methods of sex selection: preconception sperm sorting and pre-implantation genetic
diagnosis (PGD) (Bhatia, 2018). Preconception sperm sorting involves staining the sperm with a
fluorescent dye and then leading them past a laser beam where the difference in DNA content between
X- and Y-bearing sperm is visible. PGD creates zygotes within the laboratory by removing eggs from the
woman and fertilizing them with sperm. Three days after fertilization a cell from each cluster of cells is
extracted to examine the chromosomes and determine whether or not it contains a Y chromosome (i.e.,
whether it is female or male). The desired male or female embryos are then implanted into the woman’s
uterus. The second type of sex selection, sperm sorting, entails spinning sperm in a centrifuge to
separate those that carry an X or Y chromosome. Sperm with the desired chromosomes are then used to
fertilize the ovum either vaginally or through in vitro fertilization.
As sex selection becomes more widely available, parents may seek to choose the sex of their child
because of personal desires, such as to create family balance or to conform to cultural valuing of one sex
over the other, rather than to avoid transmitting genetic disorders (Bowman-Smart et al., 2020;
Robertson & Hickman, 2013). Without the ability to choose a child’s sex, some parents might choose not
to reproduce (Bowman-Smart et al., 2020). Critics argue that sex selection can lead down a “slippery
slope” of selecting for other characteristics—hair color, eye color, intelligence, and more (Dondorp et al.,
2013). Moreover, a children’s biological sex is different from their gender, the gender-associated
behaviors that they adopt (as we will discuss later in this book). (Brown & Stone, 2016). Might children
born from gender selection be expected to act in certain sex-typical ways and if they do not, might that
disappoint parents?
Others express concerns about societal sex ratio imbalances if sex selection becomes widely practiced
(Colls et al., 2009; Robertson & Hickman, 2013). Asian and Eastern European cultures, such as China,
South Korea, India, and Azerbaijan, traditionally favor boys over girls (Tafuro & Guilmoto, 2020). Sex ratio
imbalances favoring males have occurred in India and China because of female infanticide, neglect and
maltreatment, gender-driven abortion, and China’s one-child family policy (discussed in Chapter 10)
(Bhatia, 2010; Ethics Committee of the American Society for Reproductive Medicine, 2001; Ritchie &
Roser, 2019). Thirty-six countries have national laws or policies on sex selection (Mohapatra, 2013). Most
prohibit sex selection for nonmedical reasons—Austria, New Zealand, South Korea, Switzerland,
Australia, Belgium, Netherlands, India, China, Portugal, Russia, Spain, Turkey, the United Kingdom, and
Vietnam ban sex selection (Mohapatra, 2013). The European Union bans socially, nontherapeutically
motivated prenatal sex selection (Council of Europe, 1997). The United States does not have a formal
policy regarding sex selection (Deeney, 2013). Most fertility clinics offer it (Bayefsky, 2018). Sex selection
remains hotly debated in medical journals, with hospital and university ethics boards, and the public.
Thinking in Context: Applied Developmental Science
1. Provide advice to Eduardo and Natia, a couple in their mid-30s who are seeking reproductive
assistance. What are their options, and what are the advantages and disadvantages of each?
2. What do you think about parents choosing the sex of their children? In your view, under what
conditions is sex selection acceptable?
3. If you were able to choose and selectively reproduce characteristics, apart from sex, what might
you choose? Why or why not? What are some practical or ethical issues in selecting a child’s
characteristics or “designing” a child?
Thinking in Context: Intersectionality
Assisted reproductive technology is not easily available to all individuals and couples. What are some of
the barriers to obtaining assisted reproductive technology? Which barriers are most challenging? To
what degree is there a need for equity in access to reproductive technology? Why? If so, how might we
begin?
REPRODUCTIVE CHOICES: ADOPTION
LEARNING OBJECTIVE
2.4 Compare and contrast characteristics and outcomes of adoption, transracial adoption, and
international adoption.
Another reproductive option for prospective parents is adoption. Adults, heterosexual and same-sex
individuals and couples, have similar motives for adopting children as those who raise biological children
(Jennings et al., 2014; Malm & Welti, 2010). They include reasons such as valuing family ties, continuing a
family line, feeling that parenting is a life task, and the desire for a nurturing relationship with a child
(Costa & Tasker, 2018; Goldberg et al., 2012).
Adoptive children tend to be raised by parents with higher levels of education and income than other
children (Drozd et al., 2018). This is partly due to self-selection and partly because of the screening that
adoptive parents must undergo before they can adopt. Adoptive parents have a strong desire and are
highly motivated to become parents.
Adoption and Child Outcomes
Overall, adoptive children tend to spend more time with their parents and have more educational
resources than other children (Zill, 2015). In kindergarten, they do not differ from nonadopted children
in reading and math scores (Tan et al., 2017). Yet many adopted children show less engagement in class
and tend to have more academic difficulties than other children. Longitudinal research suggests that
adoption is associated with lower academic attainment achievement across childhood, adolescence, and
emerging adulthood compared with nonadopted comparison groups (Brown et al., 2017; Wiley, 2017).
Adopted children may show more behavior problems and adjustment difficulties than their nonadoptive
peers, in some cases persisting into adulthood (Brown et al., 2017; Palacios & Brodzinsky, 2010). For
many children, emotional difficulties are transitional, perhaps accounting for mixed findings in
outcomes. Some research suggests no differences between adopted and nonadopted children in
internalizing problems, such as anxiety and depression (Brown et al., 2019; Wiley, 2017). This is
supported by longitudinal research that followed adoptees into middle adulthood and showed few
differences in psychological distress; differences were accounted for by differences in childhood family
circumstances (Sehmi et al., 2020).
Children’s experiences prior to adoption, especially neglect and maltreatment, and their developmental
status at the time of adoption influence their short- and long-term adjustment (Balenzano et al., 2018;
Finet et al., 2018; Hornfeck et al., 2019). Adopted children tend to experience greater stress prenatally,
early in life, prior to adoption, and during the adoption process that influences their long-term
adjustment after adoption (Grotevant & McDermott, 2014; Wiley, 2017). The quality of adoptive parent–
child relationships influences children’s outcomes and the long-term effects of preadoption adversity
(Farr & Grotevant, 2019). Children who develop a close bond with adoptive parents tend to show better
emotional understanding and regulation, social competence, and also self-esteem (Drozd et al., 2018;
Juffer & van IJzendoorn, 2007; Schoemaker et al., 2019). This is true also of children who have
experienced emotional neglect, and those effects hold regardless of the age at adoption (Barone et al.,
2017).
Adults choose to adopt for a variety of reasons, such as infertility, the desire
to raise a child alone or with a same-sex partner, and to provide a home for a
child in need.
iStock/CREATISTA
Transracial Adoption
It is estimated that transracial adoptions, in which a child (typically of color) is adopted by parents of a
different race (most often white), account for about one-quarter of adoptions (Marr, 2017). Transracial
adoption is associated with academic delays, social and emotional risks such as bullying, racial and
ethnic microaggression, and adoption stigma (Branco & Brott, 2018).
Transracial adoptive children, and especially adolescents, may face challenges in ethnic and racial
socialization and identity development (Wiley, 2017). Although racial identity development may happen
more slowly and entail more challenges for transracially adopted adolescents than nonadopted racial
minority adolescents, most develop a firm sense of identity (Hrapczynski & Leslie, 2019). Racial and
ethnic socialization is associated with healthy adoptee outcomes, including well-being and positive selfesteem (Montgomery & Jordan, 2018).
Parents can foster their adoptive children’s ethnic and racial socialization by exposing children to their
racial and ethnic heritage and provide opportunities for children to learn about and interact with people
who identify with their birth race and ethnicity (Hrapczynski & Leslie, 2019). Research with transracially
adopted Mexican American adoptees suggests that ethnic identity was associated with living in diverse
neighborhoods, parents’ awareness of the children’s culture, and encouragement for children to learn
about and participate in their culture (Montgomery & Jordan, 2018). Close relationships with adoptive
parents who engage them with cultural activities are positively associated with academic performance
(Montgomery et al., 2020). Transracially adopted children show the most positive self-esteem and wellbeing outcomes and the least distress when they integrate their racial and cultural heritage with their
adoptive culture rather than denying either their adoptive or racial heritage (Mohanty, 2015).
International Adoption
In many countries throughout the world, children without parents are reared in orphanages, often with
substandard conditions—without adequate food, clothing, or shelter and with poorly trained caregivers.
Such orphanages in countries such as China, Ethiopia, Ukraine, Congo, and Haiti, account for over twothirds of internationally adopted children (U.S. Department of State, 2014). Underfunded and
understaffed orphanages often provide poor, nonnurturing care for children, increasing the risks for
malnutrition, infections, physical handicaps, and growth retardation (The Leiden Conference on the
Development and Care of Children Without Permanent Parents, 2012). With high infant-to-caregiver
ratios, children available for adoption often spend a significant amount of time deprived of consistent
human contact.
Few internationally adopted children enter the United States healthy and at age-appropriate
developmental norms. Physical growth stunting is directly associated with the length of
institutionalization, but catch-up growth is commonly seen after adoption (Wiley, 2017; Wilson &
Weaver, 2009). As with growth, the time spent in an orphanage predicts the degree of developmental
delay (Jacobs et al., 2010). Longer institutionalization is associated with delays in development of
language, fine motor skills, social skills, attention, and other cognitive skills (Mason & Narad, 2005; Wiik
et al., 2011).
Speech and language delays are among the most consistent deficiencies experienced by internationally
adopted children, especially those adopted after the age of 1 (Eigsti et al., 2011). Many children reach
normative age expectations 1 to 2 years postadoption (Glennen, 2014; Rakhlin et al., 2015). Generally,
the younger the child is at adoption, the more quickly he or she will adapt to the new language and
close any gaps in language delays (Glennen & Masters, 2002; Mason & Narad, 2005). Virtually all
internationally adopted children of all ages show catch-up cognitive growth but many may show longterm deficits in executive function related to the neurological effects of their preadoption experiences,
such as deprivation (Canzi et al., 2018; Finet et al., 2019; Merz et al., 2016). The presence of a high-quality
parent–child relationship promotes development of language, speech, and academic outcomes
(Glennen, 2014; Harwood et al., 2013).
International adoption has become more common in the United States, and
there are important challenges that adopted children and families face.
iStock/ParkerDeen
As adolescents, all children struggle to come to a sense of identity, to figure out who they are. This
struggle may be challenging for internationally adopted children who may wonder about their native
culture and homeland (Rosnati et al., 2015). Frequently, adolescents may want to discuss and learn more
yet inhibit the desire to talk about this with parents (Garber & Grotevant, 2015). Parents who assume a
multicultural perspective and provide opportunities for their children to learn about their birth culture
support adopted children’s development and promote healthy outcomes (Pinderhughes et al., 2015).
Like transracially adopted children, internationally adopted children seek to understand their birth
culture and integrate their birth and adopted cultures into their sense of self (Grotevant et al., 2017). A
positive sense of ethnic identity is associated with positive outcomes such as self-esteem in international
adoptees (Mohanty, 2015). Although there are individual differences in the degree of resilience and in
functioning across developmental domains, adopted children overall show great developmental gains
and resilience in physical, cognitive, and emotional development (Misca, 2014; Palacios et al., 2014;
Wilson & Weaver, 2009).
Thinking in Context: Intersectionality
1. After many unsuccessful attempts to conceive, a couple in their 40s is considering adopting a child
of a different race. What can they expect? What challenges might they encounter?
2. In what ways might the match between the race or ethnicity of the child and parent influence the
family’s adaptation? Might you expect differences depending on the match between an adoptive
parent or child who is Black, white, Latinx, or Asian?
3. Do other factors, such as child's and parent’s age, socioeconomic status, or geographic location
influence adaptation? Why or why not?
4. What can parents do to support their adopted child of a different race?
Thinking in Context: Lifespan Development
1. In your view, what are the most important challenges internationally adopted infants and their
families face? Identify sources and forms of support that might help adopted infants and their
parents.
2. At what point in development does an understanding of culture become important in aiding
children’s adjustment to an adoptive home?
3. As adolescents, many adopted children are driven to learn about their biological origins. How can
adoptive parents help their children understand their heritage and adapt to their environment?
PRENATAL DIAGNOSIS
LEARNING OBJECTIVE
2.5 Summarize prenatal diagnostic methods and how genetic disorders may be treated prenatally.
Virtually all pregnant women undergo examinations to determine the health of the fetus. Some women
experienced heightened risk for fetal abnormalities. Prenatal testing is recommended when genetic
counseling has determined a risk for genetic abnormalities, when the woman is older than age 35, when
both parents are members of an ethnicity at risk for particular genetic disorders, or when fetal
development appears abnormal (Barlow-Stewart & Saleh, 2012). Technology has advanced rapidly,
equipping professionals with an array of tools to assess the health of the fetus.
Methods of Prenatal Diagnosis
The most widespread and routine diagnostic procedure is ultrasound, in which high-frequency sound
waves directed at the mother’s abdomen provide clear images of the womb represented on a video
monitor. Ultrasound enables physicians to observe the fetus, measure fetal growth, judge gestational
age, reveal the sex of the fetus, detect multiple pregnancies (twins, triplets, etc.), and determine physical
abnormalities in the fetus. Many deformities can be observed, such as cardiac abnormalities, cleft palate,
and microencephaly (small head size). At least 80% of women in the United States receive at least one
prenatal ultrasound scan (Sadler, 2018). Three or four screenings over the duration of pregnancy are
common in order to evaluate fetal development. Repeated ultrasound of the fetus does not appear to
affect growth and development (Abramowicz, 2019; Stephenson, 2005).
Ultrasound technology provides clear images of the womb, permitting
physicians to observe the fetus, measure fetal growth, judge gestational age,
reveal the sex of the fetus, detect multiple pregnancies, and determine
physical abnormalities in the fetus.
iStock/Chris Ryan
Fetal MRI applies MRI technology to image the fetus’ body and diagnose malformations (Aertsen et al.,
2020). It is often used as a follow-up to ultrasound imaging in order to provide more detailed views of
any suspected abnormalities (Milani et al., 2015). Fetal MRI can detect abnormalities throughout the
body, including the central nervous system (Griffiths et al., 2017; Masselli et al., 2020). MRI in the
obstetrical patient is safe for mother and fetus in the second and third trimesters, but it is expensive and
has limited availability in some areas (Patenaude et al., 2014).
Amniocentesis is a prenatal diagnostic procedure in which a small sample of the amniotic fluid that
surrounds the fetus is extracted from the mother’s uterus through a long, hollow needle that is guided
by ultrasound as it is inserted into the mother’s abdomen (Odibo, 2015). The amniotic fluid contains
fetal cells, which are grown in a laboratory dish in order to create enough cells for genetic analysis.
Genetic analysis is then performed to detect genetic and chromosomal anomalies and defects.
Amniocentesis is less common than ultrasound, as it poses greater risk to the fetus, but it is safe
(Homola & Zimmer, 2019). It is recommended for women aged 35 and over, especially if the woman and
partner are both known carriers of genetic diseases (Vink & Quinn, 2018a). Usually amniocentesis is
conducted between the 15th and 18th week of pregnancy. Conducted any earlier, an amniocentesis may
increase the risk of miscarriage (Akolekar et al., 2015). Test results generally are available about two
weeks after the procedure because it takes that long for the genetic material to grow and reproduce to
the point where it can be analyzed.
During amniocentesis, ultrasound is used to guide the insertion of a long,
hollow needle into the mother’s abdomen in order to extract a sample of the
amniotic fluid that surrounds the fetus. The amniotic fluid contains fetal cells,
which are grown in a laboratory dish and tested for genetic and
chromosomal anomalies and defects.
Saturn Stills/Science Source
Chorionic villus sampling (CVS) also samples genetic material and can be conducted earlier than
amniocentesis, between 9 and 12 weeks of pregnancy (Vink & Quinn, 2018b). CVS requires studying a
small amount of tissue from the chorion, part of the membrane surrounding the fetus. The tissue sample
is obtained through a long needle inserted either abdominally or vaginally, depending on the location of
the fetus. Results are typically available about one week following the procedure. CVS is relatively
painless and, like amniocentesis, has a 100% diagnostic success rate. Generally, CVS poses few risks to
the fetus (Salomon et al., 2019; Shim et al., 2014). But CVS should not be conducted prior to 10 weeks
gestation as some studies suggest an increased risk of limb defects and miscarriages (Shahbazian et al.,
2012).
Noninvasive prenatal testing (NIPT) screens the mother’s blood to detect chromosomal abnormalities.
Cell-free fetal DNA (chromosome fragments that result in the breakdown of fetal cells) circulates in
maternal blood in small concentrations that can be detected and studied by sampling the mother’s
blood (Hartwig et al., 2017; Warsof et al., 2015). Testing can be done after 10 weeks, typically between 10
and 22 weeks. Given that the test involves drawing blood from the mother, there is no risk to the fetus.
The use of NIPT has increased dramatically in the United States and other countries (Hui et al., 2017).
NIPT can provide accurate sex determination, but NIPT cannot detect as many chromosomal
abnormalities as amniocentesis or CVS and is less accurate (Hartwig et al., 2017; Villela et al., 2019).
Researchers have identified the entire genome sequence using NIPT, suggesting that someday, NIPT
may be as effective as other, more invasive techniques (Tabor et al., 2012). Pregnant women and their
partners, in consultation with their obstetrician, should carefully weigh the risks and benefits of any
procedure designed to monitor prenatal development. Table 2.6 summarizes methods of prenatal
diagnosis.
Table 2.6 Methods of Prenatal Diagnosis
Ultrasound
Explanation
High-frequency sound waves directed
at the mother’s abdomen provide clear
images of the womb projected onto a
video monitor.
Amniocentesis A small sample of the amniotic fluid
that surrounds the fetus is extracted
from the mother’s uterus through a
long, hollow needle inserted into the
mother’s abdomen. The amniotic fluid
contains fetal cells. The fetal cells are
grown in a laboratory dish in order to
create enough cells for genetic
analysis.
Advantages
Ultrasound
enables physicians
to observe the
fetus, measure
fetal growth,
reveal the sex of
the fetus, and to
determine
physical
abnormalities in
the fetus.
It permits a
thorough analysis
of the fetus’s
genotype. There is
a 100% diagnostic
success rate.
Disadvantages
Many abnormalities and
deformities cannot be
easily observed.
Safe, but poses a
greater risk to the fetus
than ultrasound.
If conducted before the
15th week of pregnancy,
it may increase the risk
of miscarriage.
Chorionic
villus
sampling
(CVS)
Explanation
Chorionic villus sampling requires
studying a small amount of tissue from
the chorion, part of the membrane
surrounding the fetus, for the presence
of chromosomal abnormalities. The
tissue sample is obtained through a
long needle inserted either
abdominally or vaginally, depending
on the location of the fetus.
Advantages
It permits a
thorough analysis
of the fetus’
genotype.
CVS is relatively
painless, and
there is a 100%
diagnostic success
rate.
Disadvantages
It may pose a higher
rate of spontaneous
abortion and limb
defects when conducted
prior to 10 weeks’
gestation.
Can be conducted
earlier than
amniocentesis,
between 10 and
12 weeks.
Fetal MRI
Uses a magnetic scanner to record
detailed images of fetal organs and
structures.
Provides the most
detailed and
accurate images
available.
Noninvasive
prenatal
testing (NIPT)
Cell-free fetal DNA are examined by
drawing blood from the mother.
There is no risk to
the fetus. It can
diagnose several
chromosomal
abnormalities.
It is expensive. At
present there is no
evidence to suggest
that it is harmful to the
fetus.
It cannot yet detect the
full range of
abnormalities.
It may be less accurate
than other methods.
Researchers have
identified the entire
genome sequence using
NIPT, suggesting that
someday NIPT may be
as effective as other,
more invasive
techniques.
Sources: Akolekar et al., 2015; Chan et al., 2013; Gregg et al., 2013; Odibo, 2015; Shahbazian et al., 2012;
Shim et al., 2014; Theodora et al., 2016.
Prenatal Treatment of Genetic Disorders
What happens when a genetic or chromosomal abnormality is found? Advances in genetics and in
medicine have led to therapies that can be administered prenatally to reduce the effects of many
genetic abnormalities. Fetoscopy is a technique that utilizes a small camera, inserted through a small
incision on the mother’s abdomen or cervix and placed into the amniotic sac, which encases the fetus, to
examine and perform procedures on the fetus during pregnancy. Risks of fetoscopy include infection,
rupture of the amniotic sac, premature labor, and fetal death. However, when serious abnormalities are
suspected, fetoscopy permits a visual assessment of the fetus, which aids in diagnosis and treatment.
Hormones and other drugs, as well as blood transfusions, can be given to the fetus by inserting a needle
into the uterus (Fox & Saade, 2012; Lindenburg et al., 2014). Surgeons rely on the images provided by
fetoscopy to surgically repair defects of the heart, lungs, urinary tract, and other areas (Deprest et al.,
2010; Peiro & Scorletti, 2019; Sala et al., 2014).
In addition, researchers believe that one day we may be able to treat many heritable disorders through
the use of gene therapy by synthesizing normal genes to replace defective ones. It may someday be
possible to sample cells from an embryo, detect harmful genes and replace them with healthy ones, then
return the healthy cells to the embryo where they reproduce and correct the genetic defect (Coutelle &
Waddington, 2012; Peranteau & Flake, 2020). This approach has been used to correct certain heritable
disorders in animals and holds promise for treating humans (Neff, 2019).
Thinking in Context: Applied Developmental Science
Suppose that you are a health care provider tasked with explaining prenatal diagnostic choices to a 38year-old woman pregnant with her first child. How would you explain the various choices? What
information would you provide about their purpose and the advantages and disadvantages of each?
Which tests are most relevant to your patient? What would you advise? Why?
HEREDITY AND ENVIRONMENT: BEHAVIOR GENETICS
LEARNING OBJECTIVE
2.6 Provide an introduction to the field of behavior genetics, including representative findings.
Our brief introduction to the processes of heredity illustrates the complexity of genetic inheritance. Our
genotype, or genetic makeup, inherited from our biological parents, is a biological contributor to all of
our observable traits, from hair and eye color to personality, health, and behavior. However, genotypes
alone do not determine our phenotype, the traits, characteristics, or personalities that we display.
Phenotypes result from the interaction of genotypes and our experiences.
Methods of Behavior Genetics
Behavior genetics is the field of study that examines how genes and experience combine to influence
the diversity of human traits, abilities, and behaviors (Knopik et al., 2017; Plomin, 2019). Behavior
geneticists have discovered that even traits with a strong genetic component, such as height, are
modified by environmental influences (Jelenkovic et al., 2016). Moreover, most human traits, such as
intelligence, are influenced by multiple genes, and there are often multiple variants of each gene and
each might interact with the environment in a different way (Briley et al., 2019; Plomin, 2019).
Behavior geneticists seek to estimate the heritability of specific traits and behaviors. Heritability refers to
the extent to which variation among people on a given characteristic is due to genetic differences. The
remaining variation not due to genetic differences is instead a result of the environment and
experiences. Heritability research therefore examines the contributions of the genotype but also
provides information on the role of experience in determining phenotypes (Fowler-Finn & Boutwell,
2019; Nivard et al., 2017). Behavior geneticists assess the hereditary contributions to behavior by
conducting selective breeding and family studies.
Selective breeding studies entail deliberately modifying the genetic makeup of animals to examine the
influence of heredity on attributes and behavior. Mice can be bred to be very physically active or
sedentary by mating highly active mice only with other highly active mice and, similarly, breeding mice
with very low levels of activity with each other. Over subsequent generations, mice bred for high levels of
activity become many times more active than those bred for low levels of activity (Schwartz et al., 2018).
Selective breeding in rats, mice, and other animals such as chickens has revealed genetic contributions
to many traits and characteristics, such as aggressiveness, emotionality, sex drive, and even maze
learning (Bubac et al., 2020).
For many reasons, especially ethical reasons, people cannot be selectively bred. However, we can
observe people who naturally vary in shared genes and environment. Behavior geneticists conduct
family studies to compare people who live together and share varying degrees of relatedness. Two kinds
of family studies are common: twin studies and adoption studies (York, 2020). Twin studies compare
identical and fraternal twins to estimate how much of a trait or behavior is attributable to genes. Recall
that identical (monozygotic) twins share 100% of their genes because they originated from the same
zygote. Like all nontwin siblings, fraternal (dizygotic) twins share 50% of their genes as they resulted
from two different fertilized ova and two genetically different zygotes. If genes affect a given attribute,
identical twins should be more similar than fraternal twins because identical twins share 100% of their
genes, whereas fraternal twins share about half.
Adoption studies, on the other hand, compare the degree of similarity between adopted children and
their biological parents whose genes they share (50%) and their adoptive parents with whom they share
an environment but not genes (York, 2020). If the adopted children share similarities with their biological
parents, even though they were not raised by them, it suggests that the similarities are genetic. The
similarities are influenced by the environment if the children are more similar to their adoptive parents.
Observations of adoptive siblings also shed light on the extent to which attributes and behaviors are
influenced by the environment. The degree to which two genetically unrelated adopted children reared
together are similar speaks to the role of environment. Comparisons of identical twins reared in the
same home with those reared in different environments can also illustrate environmental contributions
to phenotypes. If identical twins reared together are more similar than those reared apart, an
environmental influence can be inferred.
Genetic Influences on Personal Characteristics
Research examining the contribution of genotype and environment to intellectual abilities has found a
moderate role for heredity. Twin studies have shown that identical twins consistently have more highly
correlated intelligence scores than do fraternal twins (Plomin, 2019). A classic study of intelligence in
over 10,000 twin pairs showed a correlation of .86 for identical and .60 for fraternal twins (Plomin &
Spinath, 2004). Table 2.7 summarizes the results of comparisons of intelligence scores from individuals
who share different genetic relationships with each other. Note that correlations for all levels of kin are
higher when they are reared together, supporting the role of environment. Average correlations also rise
with increases in shared genes.
Table 2.7 Average Correlation of Intelligence Scores From Family Studies for Related and Unrelated Kin
Reared Together or Apart
MZ twins (100% shared genes)
DZ twins (50% shared genes)
Siblings (50% shared genes)
Biological parent/child (50% shared genes)
Half-siblings (25% shared genes)
Unrelated (adopted) siblings (0% shared genes)*
Nonbiological parent/child (0% shared genes)*
Reared Together
.86
.60
.47
.42
.31
.34
.19
Reared Apart
.72
.52
.24
.22
—
—
—
Source: Adapted from Bouchard & McGue (1981).
Notes: * Estimated correlation for individuals sharing neither genes nor environment = .0; MZ =
monozygotic; DZ = dizygotic.
Genes contribute to many other traits, such as sociability, temperament, emotionality, and susceptibility
to various illnesses such as obesity, heart disease and cancer, anxiety, poor mental health, and a
propensity to be physically aggressive (Bralten et al., 2019; Goodarzi, 2018; Morneau-Vaillancourt et al.,
2019; Purves et al., 2019; Trucco et al., 2018). Yet even traits that are thought to be heavily influenced by
genetics can be modified by physical and social interventions. Growth, body weight, and body height are
largely predicted by genetics, yet environmental circumstances and opportunities influence whether
genetic potentials are realized (Dubois et al., 2012; Jelenkovic et al., 2016). Even identical twins who
share 100% of their genes are not 100% alike. Those differences are due to the influence of
environmental factors, which interact with genes in a variety of ways.
Thinking in Context: Applied Developmental Science
Imagine that you are a researcher planning to conduct a twin and an adoption study on intelligence,
personality, academic achievement, or another topic.
1. What are the advantages and disadvantages of each method?
2. What are some challenges in obtaining participants for these studies?
3. Using the twin approach, how might you determine the genetic and environmental influence on
your topic of interest? How does this differ in adoptive studies?
4. What conclusions do you draw about these two types of studies? Which do you prefer and why?
GENE–ENVIRONMENT INTERACTIONS
LEARNING OBJECTIVE
2.7 Describe the interaction of heredity and environment, including gene–environment correlations,
gene–environment interactions, and the epigenetic framework.
“You two are so different. Deondre and Denzel, are you sure you’re twins?” kidded their aunt. As
fraternal twins, Deondre and Denzel share 50% of their genes and are reared in the same home. One
might expect them to be quite similar, but their similar genes are not the whole story. Genes and the
environment work together in complex ways to determine our characteristics, behavior, development,
and health (Morgan et al., 2020; Ritz et al., 2017). Gene–environment interactions refer to the dynamic
interplay between our genes and our environment. Several principles illustrate these interactions.
Range of Reaction
The effects of the environment depend on the genetic makeup of the individual (Briley et al., 2019).
Everyone has a different genetic makeup and therefore responds to the environment in a unique way. In
addition, any one genotype can be expressed in a variety of phenotypes. There is a range of reaction
(see Figure 2.5), a wide range of potential expressions of a genetic trait, depending on environmental
opportunities and constraints (Gottlieb, 2007). Consider height. Height is largely a function of genetics,
yet an individual may show a range of sizes depending on environment and behavior (Jelenkovic et al.,
2016). Consider children born to two very tall parents. They may have the genes to be tall, but unless
they have adequate nutrition, they will not fulfill their genetic potential for height. In societies in which
nutrition has improved dramatically over a generation, it is common for children to tower over their
parents. The enhanced environmental opportunities, in this case nutrition, enabled the children to fulfill
their genetic potential for height. Therefore, a genotype sets boundaries on the range of possible
phenotypes, but the phenotypes ultimately displayed vary in response to different environments
(Manuck & McCaffery, 2014; Morgan et al., 2020). In this way, genetics sets the range of development
outcomes and the environment influences where, within the range, that person will fall. However, gene–
environment interactions are complex and often difficult to predict, partly because individuals vary in
their sensitivity to environmental stimuli (Belsky & Hartman, 2014). Some children may be more affected
by environmental stimuli due to their genetic makeup (Briley et al., 2019).
Description
Figure 2.5 Range of Reaction
Source: Adapted from Gottlieb (2007).
Canalization
Some traits illustrate a wide reaction range. Others are examples of canalization, in which heredity
narrows the range of development to only one or a few outcomes. Canalized traits are biologically
programmed, and only powerful environmental forces can change their developmental path (Flatt, 2005;
Posadas & Carthew, 2014; Takahashi, 2019). Infants follow an age-related sequence of motor
development, from crawling, to walking, to running. Around the world, most infants walk at about 12
months of age. Generally, only extreme experiences or changes in the environment can prevent this
developmental sequence from occurring (Adolph & Franchak, 2017). Children reared in impoverished
international orphanages and exposed to extreme environmental deprivation demonstrated delayed
motor development, with infants walking 5months to a year later than expected (Miller et al., 2008;
Chaibal et al., 2016).
Motor development is not entirely canalized because some minor changes in the environment can
subtly alter its pace and timing. Practice facilitates stepping movements in young infants, prevents the
disappearance of stepping movements in the early months of life, and leads to an earlier onset of
walking (Adolph & Hoch, 2019). These observations demonstrate that even highly canalized traits, such
as motor development, which largely unfolds via maturation, can be subtly influenced by contextual
factors.
Gene–Environment Correlations
Heredity and environment are each powerful influences on development. Not only do they interact, but
environmental factors often support hereditary traits (Briley et al., 2019; Saltz, 2019; Scarr & McCartney,
1983). Gene–environment correlation refers to the finding that many genetically influenced traits tend
to be associated with environmental factors that promote their development (Lynch, 2016). That is,
genetic traits influence children’s behavior, which is often supported or encouraged by the environment
(Knafo & Jaffee, 2013). There are three types of gene–environment correlations: passive, reactive, and
active.
Parents create homes that reflect their own genotypes. Because parents are genetically similar to their
children, the homes that parents create support their own preferences but they also correspond to their
child’s genotype—an example of a passive gene–environment correlation (Wilkinson et al., 2013). It is a
passive gene–environment correlation because it occurs regardless of the child’s behavior. Parents might
provide genes that predispose a child to develop music ability and create a home environment that
supports the development of music ability, such as by playing music in the home and owning musical
instruments (Corrigall & Schellenberg, 2015) (Figure 2.6). This type of gene–environment correlation
tends to occur early in life because parents create rearing environments for their infants and young
children.
Description
Figure 2.6 Gene–Environmental Correlation
Sources: iStock/Signature; iStock/Essentials; iStock/Essentials
People naturally evoke responses from others and the environment, just as the environment and the
actions of others evoke responses from the individual. In an evocative gene–environment correlation, a
child’s genetic traits (e.g., personality characteristics including openness to experience) influence the
social and physical environment, which shape development in ways that support the genetic trait (Pieters
et al., 2015; Saltz, 2019). Active, happy infants tend to receive more adult attention than do passive or
moody infants (Deater-Deckard & O’Connor, 2000), and even among infant twins reared in the same
family, the more outgoing and happy twin receives more positive attention than does the more subdued
twin (Deater-Deckard, 2001). Why? Babies who are cheerful and smile often influence their social world
by evoking smiles and affection from others, including their parents, which in turn support the tendency
to be cheerful (Klahr et al., 2013). In this way, genotypes influence the physical and social environment to
respond in ways that support the genotype. To return to the music example, a child with a genetic trait
for music talent will evoke pleasurable responses (e.g., parental approval) when the child plays music;
this environmental support, in turn, encourages further development of the child’s musical trait.
Children also take a hands-on role in shaping their development. Recall from Chapter 1 that a major
theme in understanding human development is the finding that individuals are active in their
development; here we have an example of this theme. As children grow older, they have increasing
freedom in choosing their own activities and environments. An active gene–environment correlation
occurs when the child actively creates experiences and environments that correspond to and influence
his genetic predisposition. The child with a genetic trait for interest and ability in music actively seeks
experiences and environments that support that trait, such as friends with similar interests and afterschool music classes (Corrigall & Schellenberg, 2015). This tendency to actively seek out experiences and
environments compatible and supportive of our genetic tendencies is called niche-picking (Saltz, 2019;
Scarr & McCartney, 1983).
The strength of passive, evocative, and active gene–environment correlations changes with
development, as shown in Figure 2.7 (Lynch, 2016; Scarr, 1992). Passive gene–environment correlations
are common at birth as caregivers determine infants’ experiences. Correlations between their genotype
and environment tend to occur because their environments are made by genetically similar parents
(Armstrong-Carter et al., 2021). Evocative gene–environment correlations also occur from birth, as
infants’ inborn traits and tendencies influence others, evoking responses that support their own genetic
predispositions. In contrast, active gene–environment correlations take place as children grow older and
more independent. As they become increasingly capable of controlling parts of their environment, they
engage in niche-picking by choosing their own interests and activities, actively shaping their own
development. Niche-picking contributes to the differences we see in siblings, including fraternal twins,
as they grow older. But identical twins tend to become more similar over time perhaps because they are
increasingly able to select the environments that best fit their genetic propensities. As they age, identical
twins—even those reared apart—become alike in attitudes, personality, cognitive ability, strength,
mental health, and preferences, as well as select similar spouses and best friends (McGue & Christensen,
2013; Plomin & Von Stumm, 2018; York, 2020).
Description
Figure 2.7 Development Stage and Gene–Environment Correlations
Gene–Environment (G x E) Interactions
We have seen that behavior is influenced by gene–environment interactions. Genes may provide a
reaction range through which environmental factors act. Some genes severely limit developmental
outcomes (canalization). Although behavior geneticists have learned a great deal about genetic
influences on behavior, effects are often unpredictable (Flint et al., 2020). The effects of genes vary with
environmental influences and not all genotypes respond to environmental influences in the same way
(Fowler-Finn & Boutwell, 2019).
In a classic study, Caspi et al. (2002) followed a sample of boys from birth until adulthood. Although
children who experience child maltreatment, or abuse, tend to show developmental and behavioral
problems, the effects of maltreatment varied among the boys. Upon further study, the researchers were
surprised to find that the link between maltreatment and violence varied with the gene that controls
monoamine oxidase A (MAOA), an enzyme that regulates specific chemicals in the brain. Only boys who
carried a certain form of this gene were at risk for becoming violent after experiencing maltreatment.
Specifically, there are two versions of the gene that controls MAOA: one produces high levels of the
enzyme, and the other produces low levels.
Boys who experienced abuse and other traumatic experiences were about twice as likely to develop
problems with aggression, violence, and to even be convicted of a violent crime—but only if they carried
the low-MAOA gene. Maltreated boys who carried the high-MAOA gene were no more likely to become
violent than nonmaltreated boys. In addition, the presence of the low-MAOA gene itself was not
associated with violence. The low-MAOA gene predicted violence only for boys who experience abuse
early in life. These findings have been replicated in another 30-year longitudinal study of boys
(Fergusson et al., 2011) as well as a meta-analysis of 27 studies (Byrd & Manuck, 2014).
Similar findings of an MAOA gene × environment interaction in which low MAOA, but not high MAOA,
predicts negative outcomes in response to childhood adversity has been extended to include other
mental health outcomes such as antisocial personality disorder and depression (Beach et al., 2010;
Cicchetti et al., 2007; Manuck & McCaffery, 2014; Nikulina et al., 2012). Many of these studies have
examined only males. Females show a more mixed pattern, with some studies showing that girls display
the MAOA gene × environment interaction on emotional reactivity and aggression but to a much lesser
extent than boys, whereas other studies suggest no relationship (Byrd & Manuck, 2014; Byrd et al.,
2018). The MAOA gene illustrates gene–environment interactions, but gene–environment interactions
determine the effects of many genes. The 5-HTTLPR gene, responsible for regulating specific chemicals
in the brain, interacts with environmental factors to influence parenting sensitivity, depression, stress,
and responses to trauma (Baião et al., 2020; Li et al., 2013).
We have seen that gene–environment interactions influence development and behavior. Genes may
provide a reaction range through which environmental factors act. Some genes severely limit
developmental outcomes (canalization). Although behavior geneticists have learned a great deal about
genetic influences on behavior, their effects are often unpredictable (Flint et al., 2020). Just as some
genes might increase our susceptibility to environmental risks, others might increase our sensitivity to,
and the effectiveness of, environmental interventions (Bakermans-Kranenburg & van IJzendoorn, 2015;
Chhangur et al., 2017). The effects of genes vary with environmental influences and not all genotypes
respond to environmental influences in the same way (Fowler-Finn & Boutwell, 2019). Conclusions about
gene–environment interactions pertain to populations, not individuals. Therefore, findings from behavior
genetic research cannot predict individual behavior (Turkheimer, 2019). A final important criticism of
behavior genetic research is that, like many other areas of research, its samples are not diverse.
Ethnically diverse samples and those of low socioeconomic status are underrepresented, limiting
conclusions (Sirugo et al., 2019).
Not all children exposed to adversity experience negative outcomes. Genes,
such as MAOA, influence children's sensitivity to maltreatment.
FatCamera/Getty Images
Epigenetic Framework
Development is the product of a dynamic interaction of biological and contextual forces. Genes provide
a blueprint for development, but phenotypic outcomes, individuals’ characteristics, are not
predetermined but vary with environmental factors. Recently, scientists have determined that
environmental factors do not simply interact with genes to determine people’s traits, but they can
determine how genes are expressed through a process known as epigenetics (Carlberg & Molnar, 2019;
Moore, 2017). The term epigenetics literally means “above the gene.” The epigenome is a molecule that
stretches along the length of DNA and provides instructions to genes, determining how they are
expressed—whether they are turned on or off. The epigenome carries the instructions that determine
what each cell in your body will become, whether heart cell, muscle cell, or brain cell. Those instructions
are carried out by turning genes on and off.
At birth, each cell in our body turns on only a fraction of its genes. The epigenome instructs genes to be
turned on and off over the course of development and also in response to the environment (Meaney,
2017). Epigenetic mechanisms determine how genetic instructions are carried out to determine the
phenotype (Lester et al., 2016; Pinel et al., 2018). Environmental factors such as toxins, injuries, crowding,
diet, and responsive parenting can influence the expression of genetic traits by determining what genes
are turned on and off (O’Donnell & Meaney, 2020). In this way, even traits that are highly canalized can
be influenced by the environment.
One of the earliest examples of epigenetics is the case of agouti mice, which carry the agouti gene. Mice
that carry the agouti gene have yellow fur, are extremely obese, are shaped much like a pincushion, and
are prone to diabetes and cancer. When agouti mice breed, most of the offspring are identical to the
parents—yellow, obese, and susceptible to life-shortening disease. A groundbreaking study showed that
yellow agouti mice can produce offspring that look very different (Waterland & Jirtle, 2003). The mice in
Figure 2.8 both carry the agouti gene, yet they look very different; the brown mouse is slender, lean, and
has a low risk of developing diabetes and cancer, living well into old age. Why are these mice so
different? Epigenetics. In the case of the yellow and brown mice, the phenotype of the brown mice has
been altered, but the DNA remains the same. Both carry the agouti gene, but in the yellow mouse, the
agouti gene is turned on all the time. In the brown mouse, it is turned off.
Figure 2.8 Altering the Epigenome
Source: Wikimedia/Randy Jirtle and Dana Dolinoy/Creative Commons 3.0
In 2003, Waterland and Jertle discovered that the pregnant agouti female’s diet can determine her
offspring’s phenotype. In this study, female mice were fed foods containing chemicals that attach to a
gene and turn it off. These chemical clusters are found in many foods such as onions, garlic, beets, soy,
and the nutrients in prenatal vitamins. Yellow agouti mothers fed extra nutrients passed along the agouti
gene to their offspring, but it was turned off. The mice looked radically different from them (brown) and
were healthier (lean and not susceptible to disease) even though they carried the same genes.
Epigenetic processes also influence human development. Consider brain development (O’Donnell &
Meaney, 2020). Providing infants with a healthy diet and opportunities to explore the world will support
the development of brain cells, governed by epigenetic mechanisms that switch genes on and off.
Conversely, epigenetic changes that accompany exposure to toxins or extreme trauma might suppress
the activity of some genes, potentially negatively influencing brain development. In this way, individuals'
neurological capacities are the result of epigenetic interactions among genes and contextual factors
(Lerner & Overton, 2017) (Figure 2.9). Interactions between heredity and environment change
throughout development as does the role we play in constructing environments that support our
genotypes, influence our epigenome, and determine who we become (Lickliter & Witherington, 2017).
Description
Figure 2.9 Epigenetic Framework
Source: Gottlieb (2007).
Perhaps the most surprising finding emerging from animal studies of epigenetics is that not only can the
epigenome be influenced by the environment before birth but it can be passed by males and females
from one generation to the next (Legoff et al., 2019; Szyf, 2015). This means that what you eat and do
today could affect the epigenome—the development, characteristics, and health—of your children,
grandchildren, and great-grandchildren (Bošković & Rando, 2018; Grover & Jenkins, 2020; Vanhees et
al., 2014).
Thinking in Context: Lifespan Development
1. Describe a skill or ability in which you excel. How might your ability be influenced by your genes
and your context?
a. Identify a passive gene–environment correlation that may contribute to your ability. How has
your environment influenced your ability?
b. Provide an example of an evocative gene–environment correlation. How have you evoked
responses from your context that influenced your ability?
c. Explain how your ability might reflect an active gene–environment correlation.
d. Which of these types of gene–environment correlations do you think best accounts for your
ability Why?
Thinking in Context: Biological Influences
1. Considering the research on epigenetics, what can you do to protect your epigenome? What kinds
of behavioral and contextual factors might influence your epigenome?
2. If some genes may be protective in particular contexts, should scientists learn how to turn them on?
Should scientists learn to turn off genes that might increase risks in particular contexts? Why or why
not?
APPLY YOUR KNOWLEDGE
Strapped in and buckled in the rear seat of her mother’s bicycle, 1-year-old Jenna patted her helmet as
her mother zoomed along the bike path to the beach. She giggled and kicked her legs as her mother
whooshed her through the water. As a child, Jenna loved to be outside and especially in the water. Jenna
practiced swimming at the local YMCA nearly every day and became quite skilled. Jenna’s proud mother
encouraged her daughter’s athleticism by enrolling her in swim classes. As a teenager, Jenna decided
that if she were going to become an exceptional swimmer, she would have to go to a summer swimming
camp. She researched camps and asked her mother if she could attend. Jenna further honed her skills as
a swimmer and won a college scholarship for swimming.
Many years later, Jenna was surprised to learn that she had a twin sister, Tasha. Separated at birth, Jenna
and Tasha became aware of each other in their early 40s. Jenna was stunned yet couldn’t wait to meet
her twin sister. Upon meeting, Jenna and Tasha were surprised to find that they were not exactly the
same. Whereas Jenna was athletic and lithe, Tasha was more sedentary and substantially heavier than
Jenna. Unlike Jenna, Tasha grew up in a home far from the beach and with little access to outdoor
activities. Instead, Tasha’s interest was writing. As a child, she’d write stories and share them with others.
She sought out opportunities to write and chose a college with an exceptional writing program. Both
Jenna and Tasha excelled in college, as they did throughout their education, and earned nearly identical
scores on the SAT.
Jenna and Tasha look very similar. Even the most casual observer could easily tell that they are sisters as
both have blond hair, blue eyes, and a similar facial structure. Tasha’s skin, however, is more fair and
unlined. Jenna’s face is sprinkled with freckles and darker spots formed after many days spent swimming
outside. Jenna and Tasha both are allergic to peanuts, and they both take medication for high blood
pressure. The more that Jenna and Tasha get to know each other, the more similarities they find.
1. Considering Jenna and Tasha, provide examples of three types of gene–environment correlations:
passive, evocative, and active.
2. Do you think Jenna and Tasha are monozygotic or dizygotic twins? Why or why not?
3. What role might epigenetic influences play in determining Jenna's and Tasha’s development?
CHAPTER SUMMARY
2.1
Discuss the genetic foundations of development.
Genes are composed of stretches of deoxyribonucleic acid (DNA). Most cells in the human body
reproduce through mitosis, but sex cells reproduce by meiosis, creating gametes with 23 single,
unpaired chromosomes. Some genes are passed through dominant–recessive inheritance, in which
some genes are dominant and will always be expressed, and others are recessive and will only be
expressed if paired with another recessive gene. Other patterns include incomplete dominance and
genomic imprinting. Most traits are polygenic, the result of interactions among many genes.
2.2
Identify examples of genetic disorders and chromosomal abnormalities.
Genetic disorders carried through dominant–recessive inheritance include PKU, a recessive disorder,
and Huntington disease, carried by a dominant allele. Some recessive genetic disorders, like the
gene for hemophilia, are carried on the X chromosome. Males are more likely to be affected by Xlinked genetic disorders. Fragile X syndrome is an example of a dominant–recessive disorder carried
on the X chromosome. Other X-linked genetic disorders include Klinefelter syndrome, Jacob’s
syndrome, triple X syndrome, and Turner syndrome. Some disorders, such as trisomy 21, known as
Down syndrome, are the result of chromosomal abnormalities. Others result from mutations.
2.3
Explain the choices of reproductive technology available to individuals and couples who wish to
conceive by alternative means.
Individuals and couples turn to assisted reproductive technology (ART) for a variety of reasons,
including infertility, to reduce the risk of genetic or chromosomal abnormalities, or to conceive
without a partner. Artificial insemination, the simplest ART, involves injecting sperm into a woman. In
vitro fertilization involves fertilizing ova with sperm in a dish and implanting the resulting cluster of
cells in the woman’s uterus. Surrogacy is an alternative form of reproduction in which a woman (the
surrogate) is impregnated and carries a fetus to term and agrees to turn the baby over to a woman,
man, or couple who will raise it.
2.4
Compare and contrast characteristics and outcomes of adoption, transracial adoption, and
international adoption.
Adoptive children tend to be raised by parents with higher levels of education and have more
educational resources than other children. Yet adoption is associated with lower academic
attainment achievement and sometimes transient behavior problems. For internationally adopted
children, the time spent in an orphanage predicts the degree of developmental delay, but virtually
all internationally adopted children show some catch-up cognitive growth. For both transracial and
internationally adopted children, racial and ethnic socialization is associated with healthy outcomes,
including well-being, positive self-esteem, and identity. Children’s experiences prior to adoption,
especially neglect and maltreatment, and their developmental status at the time of adoption,
influence their short- and long-term adjustment. Generally, adopted children overall show great
developmental gains and resilience in physical, cognitive, and emotional development.
2.5
Summarize prenatal diagnostic methods and how genetic disorders may be treated prenatally.
Ultrasound enables physicians to observe the fetus, measure fetal growth, judge gestational age,
and determine physical abnormalities in the fetus. Fetal MRI applies MRI technology to image the
fetus’ body and diagnose malformations, and it is often used as a follow-up to ultrasound imaging.
Amniocentesis involves extracting a small sample of the amniotic fluid that surrounds the fetus. The
extracted fetal cells are grown in a laboratory dish and then analyzed. Chorionic villus sampling
g
y
y
p g
(CVS) also samples genetic material and can be conducted earlier than amniocentesis. Noninvasive
prenatal testing (NIPT) screens the mother’s blood to detect chromosomal abnormalities, but it is
not as accurate as amniocentesis and CVS. Fetoscopy involves inserting a camera into the womb to
examine and perform procedures, including surgery, on the fetus during pregnancy.
2.6
Provide an introduction to the field of behavior genetics, including representative findings.
Behavior genetics is the field of study that examines how genes and experience combine to
influence the diversity of human traits, abilities, and behaviors. Heritability research examines the
contributions of the genotype in determining phenotypes but also provides information on the role
of experience through three types of studies: selective breeding studies, family studies, and
adoption studies. Genetics contributes to many traits, such as intellectual ability, sociability, anxiety,
agreeableness, activity level, obesity, and susceptibility to various illnesses.
2.7
Describe the interaction of heredity and environment, including gene–environment correlations,
gene–environment interactions, and the epigenetic framework.
Passive, evocative, and active gene–environment correlations illustrate how traits often are
supported by both our genes and environment. Reaction range refers to the idea that there is a
wide range of potential expressions of a genetic trait, depending on environmental opportunities
and constraints. Some traits illustrate canalization and require extreme changes in the environment
to alter their course. People’s genes and environment interact in complex ways such that the effects
of experience may vary with a person’s genes. The epigenetic framework is a model for
understanding the dynamic, ongoing interactions between heredity and environment whereby the
epigenome’s instructions to turn genes on and off throughout development are influenced by the
environment.
Key Terms
Adoption
Alleles
Amniocentesis
Artificial insemination
Behavior genetics
Canalization
Chorionic villus sampling (CVS)
Chromosomes
Dizygotic twins
DNA (deoxyribonucleic acid)
Dominant–recessive inheritance
Down syndrome
Epigenetics
Fetal MRI
Fetoscopy
py
Fragile X syndrome
Gametes
Gene–environment correlation
Gene–environment interactions
Genes
Genetic counseling
Genomic imprinting
Genotype
Hemophilia
Heritability
Incomplete dominance
In vitro fertilization
Jacob’s syndrome
Klinefelter syndrome
Meiosis
Mitosis
Monozygotic twins
Mutations
Niche-picking
Noninvasive prenatal testing
Phenotype
Phenylketonuria (PKU)
Polygenic inheritance
Range of reaction
Sickle cell trait
Surrogacy
Triple X syndrome
Turner syndrome
Ultrasound
Zygote
Descriptions of Images and Figures
Back to Figure
Out of the 23 pairs of chromosomes, 22 are matched pairs. The 23rdpair has the sex chromosomes. In
females, sex chromosomes consist of two large X-shaped chromosomes (XX). In males, they consist of
one large X-shaped chromosome and one much smaller Y-shaped chromosome (XY). In the figure, these
pairs are labeled X and Y, respectively.
Back to Figure
The genetic makeup of father is XY and that of mother is XX. The sperms may contain either X or Y
chromosomes. The egg contains only X chromosome. If the X containing sperm fertilizes the egg, a
female fetus will develop. If the Y containing sperm fertilizes an egg, then a male fetus will develop. The
chances of fertilization with X and Y containing sperms are equal.
Back to Figure
Dominant–recessive Inheritance exemplified by the inheritance of hair color in human beings. Parental
phenotypes are brown hair in father and brown hair in mother. The genotype for both is Nr. The children
can be brown hair with NN, brown hair with Nr, and red hair with rr. Among the children, one out of four
can be NN, two out of four can be Nr, and one out of four can be rr.
Back to Figure
In genomic imprinting exemplified by Prader-Willi syndrome and Angelman syndrome. If an individual
acquires the chromosome 15 abnormality from the biological father, the individual, whether a daughter
or son, will develop Prader-Willi syndrome. If the abnormal chromosome 15 arises from the mother, the
individual—again, whether it is a daughter or a son—will develop Angelman syndrome.
Back to Figure
The horizontal axis shows the Quality of Environment as deprived, average and enriched. The vertical
axis shows the Intelligence Performance (IQ) from 25 to 150 with increments. The lines represent
Genotype A, Genotype B and Genotype C. A genotype sets boundaries on the range of possible
phenotypes, but the phenotypes ultimately displayed vary in response to different environments.
Back to Figure
The cycle of events depicted indicate the passive gene–environment correlation, evocative gene–
environment correlation, and niche-picking. Photo at the top is of a guitar kept against a book shelf,
photo on the right, below, is of a girl playing guitar by sitting at the steps, and the photo on the right is
of a girl playing guitar in front of a few people. Arched arrows in the clockwise direction are placed
between the photographs.
Back to Figure
The horizontal axis show the Development Stages as Infancy, Childhood, Adolescence and Adulthood.
The vertical axis shows the Degree/Amount of Influence with Little/Low and Much/High. The lines
represent Active Gene–Environment, Evocative Gene–Environment and Passive Gene– Environment. The
strength of passive, evocative, and active gene–environment correlations changes with development.
Passive gene–environment correlations are common at birth as caregivers determine infants’
experiences. Evocative gene–environment correlations also occur from birth, as infants’ inborn traits and
tendencies influence others, evoking responses that support their own genetic predispositions. In
contrast, active gene–environment correlations take place as children grow older and more independent.
Back to Figure
Epigenetic framework depicting bidirectional influences. At the bottom, a right arrow is labelled
Individual Development. Above this, there are four parallel lines. On the left side of the line, the labels,
from bottom to top are, genetic activity, neural activity, behavior, and environment including physical,
social and cultural. Slanting up arrows are placed in line between the parallel lines, from bottom line to
top line. Slanting down arrows are placed, between the parallel lines, from top line to the bottom line.
3 THE PRENATAL PERIOD, BIRTH, AND THE NEWBORN
iStock/FatCamera
Looking down at his newborn daughter’s face, Darryl said admiringly, “She looks just like you.” His wife,
Darla, replied, “That’s what my mother said.” “I’m in awe,” said Darryl. “We—well, largely you, created a
beautiful little girl, seemingly overnight.” “Trust me,” Darla laughed, “She did not pop into existence
overnight! She took her time and it was quite a trip.”
As these new parents describe, prenatal development is a dramatic process. Over 9 months, a single cell
transforms and grows into a neonate, a newborn. Every infant is born with a unique set of characteristics
that reflect the genetic makeup of both parents. In this chapter, we discuss how prenatal development
unfolds and how individuals develop before birth.
PRENATAL DEVELOPMENT
LEARNING OBJECTIVE
3.1 Describe the three periods of prenatal development.
Conception, the union of ovum and sperm, marks the beginning of prenatal development. Over the next
38 weeks, the human progresses from fertilization to birth. During this transformation, the zygote
undergoes several periods of development, finally emerging from the womb as a neonate.
The tiny sperm is fertilizing the much larger ovum.
F. Leroy/Science Source
Conception
A woman can conceive only during a short window of time each month. About every 28 days, an ovum
bursts from one of the ovaries into the long, thin fallopian tube that leads to the uterus; this event is
known as ovulation (Figure 3.1). The ovum is the largest cell in the human body, yet it is only 1/175th of
an inch in diameter (about the size of the period at the end of this sentence). Over several days, the
ovum travels down the fallopian tube, which connects the ovaries to the uterus, while the corpus luteum,
the spot on the ovary from which the ovum was released, secretes hormones that cause the lining of the
uterus to thicken in preparation for the fertilized ovum (Sadler, 2018). If fertilization does not occur, the
lining of the uterus is shed through menstruation about 2 weeks after ovulation.
Description
Figure 3.1 Female Reproductive System
Source: Levine and Munsch (2010, p. 102).
Conception, of course, also involves the male. Each day, a man’s testes produce millions of sperm, which
are composed of a pointed head packed with 23 chromosomes’ worth of genetic material and a long
tail. During ejaculation, about 360 million, and as many as 500 million, sperm are released, bathed in a
protective fluid called semen (Moore et al., 2019). After entering the female’s vagina, sperm travel
through the cervix into the uterus and onward toward the ovum. After about 6 hours the sperm reach
the fallopian tube, where an ovum may—or may not—be present. The journey is difficult: Some sperm
get tangled up with other sperm, some travel up the wrong fallopian tube, and others do not swim
vigorously enough to reach the ovum. On average, about 300 sperm reach the ovum, if one is present
(Webster et al., 2018). Those that travel up the fallopian tube can live up to 6 days, able to fertilize a yet
unreleased ovum. The ovum, however, remains viable for about only a day after being released into the
fallopian tube.
Both sperm and the woman’s reproductive tract play a role in fertilization (Suarez, 2016). Sperm are
guided by temperature, tracking the heat of an expectant ovum, as well as by chemical signal (Li &
Winuthayanon, 2017; Lottero-Leconte et al., 2017). In the presence of an ovum, sperm become
hyperactivated, they swim even more vigorously, and the sperm’s head releases enzymes to help it
penetrate the protective layers of the ovum (Bianchi & Wright, 2016). As soon as one sperm penetrates
the ovum, a chemical reaction makes the ovum’s membrane impermeable to other sperm. The sperm’s
tail falls off, and the sperm’s genetic contents merge with that of the ovum.
This ball of cells, known as a morula, is formed at about three days after
conception. Each of these cells is identical. Differentiation has not yet begun.
Pascal Goetgheluck/Science Source
At the moment of conception, the zygote contains 46 chromosomes, half from the ovum and half from
the sperm. After fertilization, the zygote rapidly transforms into a multicelled organism. Prenatal
development takes place over three developmental periods: (1) the germinal period, (2) the embryonic
period, and (3) the fetal period.
Germinal Period (0 to 2 Weeks)
During the germinal period, also known as the period of the zygote, the newly created zygote begins
cell division as it travels down the fallopian tube, where fertilization took place, toward the uterus. About
30 hours after conception, the zygote then splits down the middle, forming two identical cells (Webster
et al., 2018). This process is called cleavage, and it continues at a rapid pace. The two cells each split to
form four cells, then eight, and so on (Figure 3.2). Each of the resulting cells is identical until about the
third set of cell divisions. This process of cell division continues rapidly. Any of these cells may become a
person (and sometimes do, in the case of monozygotic or identical twins).
Description
Figure 3.2 The Germinal Period
Source: Levine and Munsch (2010, p. 102).
Cell differentiation begins roughly 72 hours after fertilization, when the organism consists of about 16 to
32 cells. Differentiation means that the cells begin to specialize and are no longer identical. By 4 days,
the organism consists of about 60 to 70 cells formed into a hollow ball called a blastocyst, a fluid-filled
sphere with cells forming a protective circle around an inner cluster of cells from which the embryo will
develop. Implantation, in which the blastocyst burrows into the wall of the uterus, begins at about day 6
and is complete by about day 11 (Moore et al., 2019).
Embryonic Period (3 to 8 Weeks)
After implantation, during the third week after conception, the developing organism, now called an
embryo, begins the most rapid period of structural development in the lifespan. All of the organs and
major body systems form during the embryonic period. The mass of cells composing the
forms layers, which will develop into all of the major organs of the body. The
, the upper layer,
will become skin, nails, hair, teeth, sensory organs, and the nervous system. The
, the lower
layer, will become the digestive system, liver, lungs, pancreas, salivary glands, and respiratory system. The
middle layer, the
, forms later and will become muscles, skeleton, circulatory system, and
internal organs.
mesoderm
embryonic disk
ectoderm
endoderm
As the embryo develops, support structures form to protect it, provide nourishment, and remove wastes.
The amnion, a membrane that holds amniotic fluid, surrounds the embryo providing temperature
regulation, cushioning, and protection from shocks. The placenta, a principal organ of exchange
between the mother and developing organism begins to form. It contains tissue from both the mother
and embryo and, once formed, will act as a filter, enabling the exchange of nutrients, oxygen, and wastes
to occur through the umbilical cord. The placenta is also a protective barrier, preventing some toxins
from entering the embryo’s bloodstream as well as keeping the mother and embryo’s bloodstreams
separate. Many toxins are able to pass through the placenta, including drugs and chemicals, such as
alcohol, cannabis, and opioids, as we will discuss later.
About 22 days after conception marks a particularly important change. The ectoderm folds to form the
neural tube, which will develop into the central nervous system (brain and spinal cord) (Webster et al.,
2018). Now the head can be distinguished. A blood vessel that will become the heart begins to pulse
and blood begins to circulate throughout the body. During days 26 and 27, arm buds appear, followed
by leg buds on days 28 through 30 (Sadler, 2018). At about this time, a tail-like appendage extends from
the spine, disappearing at about 55 days after conception. The brain develops rapidly and the head
grows faster than the other parts of the body during the fifth week of development. The eyes, ears, nose,
and mouth begin to form during the sixth week. Upper arms, forearms, palms, legs, and feet appear. The
embryo shows reflex responses to touch.
During the seventh week, webbed fingers and toes are apparent; they separate completely by the end of
the eighth week. A ridge called the indifferent gonad appears; it will develop into the male or female
genitals, depending on the fetus’s sex chromosomes (Moore et al., 2019). The Y chromosome of the
male embryo instructs it to secrete testosterone, causing the
to create testes. In
female embryos, no testosterone is released, and the indifferent gonad produces ovaries. The sex organs
take several weeks to develop. The external genital organs are not apparent until about 12 weeks.
indifferent gonad
At the end of the embryonic period, 8 weeks after conception, the embryo weighs about one-seventh of
an ounce and is 1 inch long. All of the basic organs and body parts have formed in a very rudimentary
way. The embryo displays spontaneous reflexive movements, but it is still too small for the movements
to be felt by the mother (Hepper, 2015). Serious defects that emerge during the embryonic period often
cause a miscarriage, or spontaneous abortion (loss of the embryo); indeed, most miscarriages are the
result of chromosomal abnormalities. The most severely defective organisms do not survive beyond the
first trimester, or third month of pregnancy. It is estimated that up to 45% of all conceptions abort
spontaneously, and most occur before the pregnancy is detected (Chou et al., 2020).
Development proceeds very quickly during the embryonic period. Note the
dramatic changes from the fifth week (left) to the seventh week (right) of
prenatal development.
Petit Format/Science Source; Professor Pietro M. Motta/Science Source
Fetal Period (9 Weeks to Birth)
During the fetal period, from the ninth week to birth, the organism, called a fetus, grows rapidly, and its
organs become more complex and begin to function. Now all parts of the fetus’s body can move
spontaneously, the legs kick, and the fetus can suck its thumb (an involuntary reflex). By the end of the
12th week, the upper limbs have almost reached their final relative lengths, but the lower limbs are
slightly shorter than their final relative lengths (Sadler, 2018).
By the 14th week, limb movements are coordinated, but they will be too slight to be felt by the mother
until about 17 to 20 weeks. The heartbeat gets stronger. Eyelids, eyebrows, fingernails, toenails, and
tooth buds form. The first hair to appear is lanugo, a fine down-like hair that covers the fetus’s body; it
is gradually replaced by human hair. The skin is covered with a greasy material called the vernix caseosa,
which protects the fetal skin from abrasions, chapping, and hardening that can occur with exposure to
amniotic fluid (Moore et al., 2019). At 21 weeks, rapid eye movements begin, signifying an important
time of growth and development for the fetal brain. The brain begins to become more responsive. A
startle response has been reported at 22 to 23 weeks in response to sudden vibrations and noises
(Hepper, 2015). The startle response is a basic reflex controlled by the developing central nervous system
and is not a voluntary movement. During weeks 21 to 25, the fetus gains substantial weight, and its body
proportions become more like those of a newborn infant. Growth of the fetal body begins to catch up to
the head, yet the head remains disproportionately larger than the body at birth.
During the last 3 months of pregnancy, the fetal body grows substantially in weight and length;
specifically, it typically gains over 5 pounds and grows 7 inches. At about 28 weeks after conception,
brain development grows in leaps and bounds. The cerebral cortex develops convolutions and furrows,
taking on the brain’s characteristic wrinkly appearance (Andescavage et al., 2016). The fetal brain wave
pattern shifts to include occasional bursts of activity, similar to the sleep-wake cycles of newborns. By 30
weeks, the pupils of the eyes dilate in response to light. At 35 weeks, the fetus has a firm hand grasp and
spontaneously orients itself toward light.
Although the expected date of delivery is about 266 days, or 38 weeks, from conception (40 weeks from
the mother’s last menstrual period), about 1 in every 10 American births is premature (Centers for
Disease Control and Prevention, 2019b). The age of viability—the age at which advanced medical care
permits a preterm newborn to survive outside the womb—begins at about 22 weeks after conception
(Moore et al., 2019). Three-quarters of infants born at 22 weeks do not survive more than a few days
because their brain and lungs have not begun to function (Myrhaug et al., 2019). Although a 23-week
fetus born prematurely may survive in intensive care, its immature respiratory system places it at risk;
only about one-third of infants born at 23 weeks’ gestation survive (Esteves et al., 2016; Stoll et al., 2015).
At about 26 weeks, the lungs become capable of breathing air and the premature infant stands a better
chance of surviving if given intensive care. About 80% of infants born at 25 weeks survive, and 94% of
those born at 27 weeks also survive (Myrhaug et al., 2019). As we will discuss later in this chapter,
premature infants experience heightened risk for short- and long-term impairments and disabilities.
Premature birth has a variety of causes, including many environmental factors.
Thinking in Context: Applied Developmental Science
1. Petra noticed that her abdomen has not grown much since she became pregnant 3 months ago.
She concluded that the fetus must not undergo significant development early in pregnancy. How
would you respond to Petra?
2. What might be some of the implications of the timing of prenatal development, that is, when the
major body systems develop, for the behavior of pregnant women and those who are considering
becoming pregnant?
ENVIRONMENTAL INFLUENCES ON PRENATAL DEVELOPMENT
LEARNING OBJECTIVE
3.2 Explain how exposure to teratogens and other environmental factors can influence the prenatal
environment.
Prenatal development unfolds along a programmed path, a predictable pattern of change.
Environmental factors can interfere with the processes of prenatal development. A teratogen is an
agent, such as a disease, drug, or other environmental factor, that disrupts prenatal development,
increasing the risk of abnormalities, defects, and even death. The field of
attempts to find the
causes of birth defects so that they may be avoided. Health care providers help pregnant women and
those who intend to become pregnant to be aware of teratogens and avoid them, as much as possible,
to maximize the likelihood of having a healthy baby.
teratology
Principles of Teratology
Different teratogens affect development in different ways. Moreover, it is not always easy to predict the
harm caused by teratogens. Generally, several principles can account for the varied effects of exposure
to teratogens on prenatal development (Moore et al., 2019; Sadler, 2018).
Critical Periods
The extent to which exposure to a teratogen disrupts prenatal development depends on the stage of
prenatal development when exposure occurs. That is, there are critical periods during prenatal
development in which the developing organism is more susceptible to damage from exposure to
teratogens (Nelson & Gabard-Durnam, 2020). Exposure to teratogens during the germinal stage can
interfere with cell division and prevent implantation; during this stage, most women are unaware that
they are pregnant and the effects of teratogens often go unnoticed.
It is during the embryonic period that the embryo is most sensitive to the harmful effects of teratogens
(Webster et al., 2018). Structural defects occur when the embryo is exposed to a teratogen while that
part of the body is developing. Each organ of the body has a sensitive period in development during
which it is most susceptible to damage from teratogens such as drugs, alcohol, and environmental
contaminants (Figure 3.3). Once a body part is fully formed, it is less likely to be harmed by exposure to
teratogens. Some body parts, like the brain, remain vulnerable throughout pregnancy.
Description
Figure 3.3 Critical Periods in Prenatal Development
Source: Adapted from Moore et al. (2019).
Dose
The amount of exposure (i.e., dose level) to a teratogen influences its effects. Generally, the greater the
dose and the longer the period of exposure, the more damage to development. Teratogens also differ in
their strength. Some teratogens, like alcohol, display a powerful dose–response relationship so that
larger doses, or heavier and more frequent drinking, result in greater damage (Bandoli et al., 2019).
Individual Differences
Individuals vary in their susceptibility to particular teratogens based on the genetic makeup of both the
organism and mother, as well as the quality of the prenatal environment. Individuals’ vulnerability to a
given teratogen may vary with genetics. Although teratogens increase the risk of defects for all
organisms, responses may vary such that some organisms show severe defects, others more mild
defects, and some may display normal development (Kaminen‐Ahola, 2020). Dizygotic (fraternal) twins
may show different effects in response to alcohol exposure in the womb, with one twin showing more
adverse effects than the other (Astley Hemingway et al., 2019). The mother’s genetic makeup and the
prenatal environment (e.g., nutrition) may also increase or decrease the likelihood of teratogenic defects.
Complicated Effects
Different teratogens can cause the same birth defect, and a variety of birth defects can result from the
same teratogen. Also, some teratogenic effects may not be noticeable at birth but instead emerge later
in life (Charness et al., 2016). Sleeper effects refer to detrimental outcomes of exposure to teratogens
and early risks that appear only later in development. Infants born to women who consumed
diethylstilbestrol (DES), a hormone that was widely prescribed between 1945 and 1970 to prevent
miscarriages, were born healthy but as adults were more likely to experience problems with their
reproductive systems. Daughters born to mothers who took DES were more likely to develop a rare form
of cervical cancer, have miscarriages, and give birth to infants who were premature or low birthweight
(Conlon, 2017). As adults, they were more likely than their unexposed peers to experience heart disease,
including heart attacks (Troisi et al., 2018).
Types of Teratogens
Prenatal development can be influenced by many contextual factors, including maternal consumption of
over-the-counter (OTC), prescription, and recreational drugs; illness; environmental factors; and more.
Sometimes a pregnant woman and her doctor must make a difficult choice between forgoing a needed
prescription drug and putting the fetus at risk. In those cases, the woman and her doctor must weigh
not just the risks to the fetus but the benefits of the medication to the mother and the potential harm
from forgoing it. Frequently, the risks of continuing medication are deemed as justified to protect the
woman’s mental and physical health.
In most cases women are unaware of their pregnancies until after the first few weeks of the embryonic
stage are already past. Thus, in the real world, almost no pregnancy can be entirely free of exposure to
teratogens. But each year, about 97% of infants are born without defects (Centers for Disease Control
and Prevention, 2020; Mai et al., 2019). Next, we examine common teratogens.
Prescription and Nonprescription Drugs
More than 90% of pregnant women take prescription or OTC medications (Servey & Chang, 2014;
Stanley et al., 2019). Prescription drugs that can act as teratogens include antibiotics, certain hormones,
antidepressants, anticonvulsants, and some acne drugs (Tsamantioti & Hashmi, 2020). In several cases,
physicians have unwittingly prescribed drugs to ease pregnant women’s discomfort that caused harm to
the fetus. In the late 1950s and early 1960s, many pregnant women were prescribed a drug called
thalidomide to prevent morning sickness. However, it was found that taking thalidomide 4 to 6 weeks
after conception (in some cases, even just one dose) caused deformities of the child’s arms and legs,
and, less frequently, damage to the ears, heart, kidneys, and genitals (Fraga et al., 2016; Vargesson,
2019).
Isotretinoin, a form of vitamin A used to treat acne, is a potent teratogen associated with miscarriage as
well as severe face, heart, and central nervous system abnormalities, as well as intellectual disability
(Altıntaş Aykan & Ergün, 2020; Wilson, 2016). The teratogenic effect of isotretinoin is so severe that the
U.S. Food and Drug Administration (2010) requires that women prescribed isotretinoin take physicianadministered pregnancy tests for 2 months prior to beginning treatment and agree to use two methods
of birth control and complete a monthly pregnancy test while taking it.
Nonprescription drugs, such as diet pills and cold medicine, can also cause harm, but research on OTC
drugs lags far behind research on prescription drugs, and we know little about the teratogenic effect of
many OTC drugs (Tsamantioti & Hashmi, 2020). Frequently, research findings are mixed, with some
studies suggesting potential harm and others suggesting no ill effects of a given drug (Hussain &
Ashmead, 2017). High doses of the common painkiller aspirin may be associated with an increased risk
of miscarriage and poor fetal growth, especially when consumed early in pregnancy (Antonucci et al.,
2012). Yet low doses are often prescribed to pregnant women to prevent and treat high blood pressure
and preeclampsia (dangerously high blood pressure late in pregnancy that can cause organ damage)
(Loussert et al., 2020; Roberge et al., 2017).
More than 90% of pregnant women take prescription or over-the-counter
medications. The findings regarding the teratogenic effects of many drugs
are often mixed, with some studies suggesting potential harm and others
suggesting no ill effects of a given drug.
iStock/damircudic
Caffeine, found in coffee, tea, cola drinks, and chocolate, is the most common OTC drug consumed
during pregnancy, yet its effects on prenatal development are unclear. Some research suggests that low
doses of caffeine (200 milligrams or about one cup per day) may be safe, but prenatal caffeine exposure
is associated with low birthweight (Modzelewska et al., 2019). Larger doses of caffeine are associated
with an increased risk for miscarriage and low birthweight (Chen et al., 2014; Chen et al., 2016), leading
some researchers to advise that women abstain from caffeine altogether (Qian et al., 2020).
Alcohol
An estimated 10% to 20% of Canadian and U.S. women report consuming alcohol during pregnancy
(Alshaarawy et al., 2016; Popova et al., 2017). Alcohol abuse during pregnancy has been identified as the
leading cause of developmental disabilities (Webster et al., 2018). Fetal alcohol spectrum disorders refer
to the continuum of effects of exposure to alcohol, which vary with the timing and amount of exposure
(Hoyme et al., 2016). Fetal alcohol spectrum disorders are estimated to affect as many as 2% to 5% of
younger schoolchildren in the United States and Western Europe (May et al., 2014, 2018). At the extreme
end of the spectrum is fetal alcohol syndrome (FAS), a cluster of defects appearing after heavy prenatal
exposure to alcohol. FAS is associated with a distinct pattern of facial characteristics (such as small head
circumference, short nose, small eye opening, and small midface), pre- and postnatal growth
deficiencies, and deficits in intellectual development, school achievement, memory, visuospatial skills,
attention, language, problem-solving, motor coordination, and the combined abilities to plan, focus
attention, problem-solve, and use goal-directed behavior (Gupta et al., 2016; Loock et al., 2020; Wozniak
et al., 2019). The effects of exposure to alcohol within the womb persist throughout childhood and
adolescence and are associated with cognitive, learning, and behavioral problems from childhood and
adolescence through adulthood (Dejong et al., 2019; Mamluk et al., 2017; Mattson et al., 2019).
Fetal alcohol syndrome is associated with distinct facial characteristics,
growth deficiencies, and deficits in intellectual development, language,
motor coordination, and the combined abilities to plan, focus attention, and
problem-solve that persist throughout childhood and into adulthood.
Susan Astley PhD/University of Washington
Even moderate drinking is harmful, as children may be born displaying some but not all of the problems
of FAS,
(Hoyme et al., 2016). Consuming 7 to 14 drinks per week during pregnancy is
associated with lower birth size, growth deficits through adolescence, and deficits in attention, memory,
and cognitive development (Flak et al., 2014; Kesmodel et al., 2019; Lundsberg et al., 2015). Even less
than one drink per day has been associated with poor fetal growth, preterm delivery, and abnormal brain
activity in newborns (Mamluk et al., 2017; Shuffrey et al., 2020). Sleeper effects may also occur with
exposure to alcohol as infants exposed prenatally to as little as an ounce of alcohol a day may display no
obvious physical deformities at birth but later, as children, may demonstrate cognitive delays. Scientists
have suggested that there is no safe level of drinking (Sarman, 2018; Shuffrey et al., 2020). The only way
to be certain of avoiding alcohol-related risks is to avoid alcohol during pregnancy altogether.
fetal alcohol effects
Is maternal alcohol and substance use during pregnancy child abuse?
Jupiterimages/Getty Images
Cigarette Smoking and E-Cigarette Use
About 7% to 10%—and in some studies as many as 17%—of women report smoking cigarettes during
pregnancy (Agrawal et al., 2019; Kondracki, 2019). Every package of cigarettes sold in the United States
includes a warning about the dangers of smoking while pregnant. Fetal deaths, premature births, and
low birthweight are 1.5 to 2 times more frequent in mothers who are smokers than in those who do not
smoke (Juárez & Merlo, 2013; Soneji & Beltrán-Sánchez, 2019). Infants exposed to smoke while in the
womb are prone to congenital heart defects, respiratory problems, and sudden infant death syndrome
and, as children, show more behavior problems, have attention difficulties, and score lower on
intelligence and achievement tests (Froggatt et al., 2020; He et al., 2017; Sutin et al., 2017). Moreover,
maternal smoking during pregnancy shows epigenetic effects on offspring, influencing predispositions
g
gp g
y
pg
p g
gp
p
to illness and disease in childhood, adolescence, and even middle adulthood (Joubert et al., 2016; Kaur
et al., 2019; Nguyen et al., 2018). There is no safe level of smoking during pregnancy. Even babies born
to light smokers (one to five cigarettes per day) show poorer fetal growth and higher rates of low
birthweight than do babies born to nonsmokers (Berlin et al., 2017; Brand et al., 2019; Tong et al., 2017).
Smoking cigarettes during pregnancy can have adverse consequences.
iStock/Jan-Otto
E-cigarettes are an increasingly common alternative to traditional cigarettes. About 10% to 15% of
women report using e-cigarettes during pregnancy, and the prevalence is rising (Wagner et al., 2017;
Whittington et al., 2018). E-cigarettes are commonly believed to be “safer” than cigarettes, but there is
no research to support this view (Holbrook, 2016). Animal research suggests that exposure to e-cigarette
vapor prenatally is associated with increased risk for asthma, cognitive and neurological problems, and
poor adjustment to stress (Church et al., 2020; Nguyen et al., 2018; Sharma et al., 2017). Research with
humans is sparse and just emerging, but it suggests that e-cigarettes have similar toxic effects on
prenatal development as traditional cigarettes (Greene & Pisano, 2019; Whittington et al., 2018).
Quitting cigarette smoking and e-cigarette use before or during pregnancy reduces the risk of adverse
pregnancy outcomes (Soneji & Beltrán-Sánchez, 2019).
Marijuana
About 4% to 7% of pregnant women report using marijuana (Brown et al., 2017; Young-Wolff et al.,
2019). The effects of marijuana, also referred to as cannabis, on prenatal development are not well
understood because there are few long-term studies of its effects and existing studies vary both in
quality and in conclusions (El Marroun et al., 2018; Metz & Borgelt, 2018). The main active ingredient of
marijuana, THC, readily crosses the placenta to affect the fetus, in lower doses than experienced by the
mother (Alvarez et al., 2018). Marijuana use during early pregnancy negatively affects fetal length,
growth, and birthweight; it can lead to stillbirth, preterm birth, and a thinner cortex (the outer layer of
the brain) in late childhood, suggesting that there are long-term neurological effects (El Marroun et al.,
2016; Gunn et al., 2016).
In fact, a growing body of research suggests that exposure to THC prenatally is associated with
developmental delays as well as subtle long-term effects in cognition, including impairments in
attention, memory, and executive function as well as impulsivity in children, adolescents, and young
adults (Grant et al., 2018; Sharapova et al., 2018; Smith et al., 2016). Researchers and health practitioners
have thus concluded that it is important to educate the public about the impact of marijuana, even
medical marijuana, on pregnancy (Chasnoff, 2017).
Cocaine
Prenatal exposure to cocaine is associated with low birthweight, impaired motor skills, and reduced brain
volume at birth and in infancy (dos Santos et al., 2018; Grewen et al., 2014). One month after birth,
babies who were exposed to cocaine have difficulty regulating their arousal states and show poor
movement skills, poor reflexes, and greater excitability (Fallone et al., 2014). Prenatal cocaine exposure
has long-term effects on children through its effect on brain development, particularly the regions
associated with attention, arousal, regulation, and executive function (Bazinet et al., 2016). Prenatal
cocaine exposure has a small but lasting effect on attention and behavioral control, as well as language
skills through early adolescence (Buckingham-Howes et al., 2013; Lewis et al., 2013; Singer et al., 2015).
In adolescence and emerging adulthood, prenatal exposure to cocaine is associated with emotional
regulation and behavior problems and substance use (Min et al., 2014; Richardson et al., 2015, 2019).
Although it was once believed that parental exposure to cocaine would result in serious lifelong
cognitive deficits for all children, research suggests more subtle long-term effects (Behnke & Smith,
2013; Lambert & Bauer, 2012). The postnatal environment contributes to cocaine-exposed children’s and
adolescents’ adjustment. Once contextual factors in the home and neighborhood, such as parenting, the
caregiving environment, socioeconomic status, and exposure to violence are controlled, adolescent
behavior problems are reduced and often eliminated in preschool and elementary school children
(Buckingham-Howes et al., 2013; Viteri et al., 2015).
Animal research suggests that a long-term risk of prenatal exposure to cocaine is increased vulnerability
to cocaine abuse (Barbosa-Méndez & Salazar-Juárez, 2020). However, a recent study of human
adolescents suggests that peer substance use and depression are better predictors of adolescent
substance use than prenatal cocaine exposure (Bennett & Lewis, 2020).
Opioids
Prenatal exposure to opioids, a class of drugs that include the illegal drugs heroin and synthetic opioids
such as fentanyl, as well as pain relievers available legally by prescription, such as oxycodone, morphine,
and others, poses serious risks to development. Newborns exposed to opioids prenatally may show
signs of addiction and withdrawal symptoms, including tremors, irritability, abnormal crying, disturbed
sleep, and impaired motor control (Conradt et al., 2019; Raffaeli et al., 2017). Prenatal exposure to
opioids is associated with low birthweight, smaller head circumference, and altered brain development
in newborns (Azuine et al., 2019; Monnelly et al., 2018; Towers et al., 2019).
Children exposed to opioids prenatally tend to show difficulty with attention, managing arousal,
learning, and inhibitory control (Bazinet et al., 2016; Levine & Woodward, 2018). Throughout childhood
into adolescence, they perform more poorly than their peers on tasks measuring intelligence and
executive functioning (such as planning), more emotional and behavioral problems, and in adolescence
show reduced brain volume and smaller cortical surface area (Konijnenberg & Melinder, 2015; Nygaard
et al., 2018; Sirnes et al., 2017; Yeoh et al., 2019). Similar to cocaine exposure, the effects of prenatal
exposure to opioids are influenced by parenting and other postnatal factors (Lee et al., 2020).
Maternal Illness
Depending on the type and when it occurs, an illness experienced by the mother during pregnancy can
have grave consequences for the developing fetus. Rubella (German measles) prior to the 11th week of
pregnancy can cause a variety of defects, including blindness, deafness, heart defects, and brain damage,
but after the first trimester, adverse consequences become less likely (Bouthry et al., 2014; Singh, 2020).
Other illnesses have varying effects on the fetus. Chicken pox can produce birth defects affecting the
arms, legs, eyes, and brain; mumps can increase the risk of miscarriage (Mehta, 2016; Webster et al.,
2018). In addition to posing risks to development, some sexually transmitted infections (STIs), such as
syphilis, can be transmitted to the fetus during pregnancy (Tsimis & Sheffield, 2017). Others, such as
gonorrhea and genital herpes, can be transmitted as the child passes through the birth canal during
birth.
cquired immune deficiency syndrome (AIDS)
HIV, the virus that causes a
, a disease affecting the immune
system, can be transmitted during birth and through bodily fluids, including by breastfeeding. Infants
and children with HIV are at high risk for a range of illnesses and health conditions, including chronic
bacterial infections; heart, gastrointestinal, and lung problems; growth stunting; problems in brain
development, including brain atrophy, which contribute to cognitive and motor impairment; and delays
in reaching developmental milestones (Evans et al., 2016; Laughton et al., 2013; McHenry et al., 2018;
Sherr et al., 2009; Wedderburn et al., 2019).
Advances in our understanding of HIV have resulted in a dramatic decline in risk of mother-to-child
transmission of HIV. The use of cesarean delivery, prescribing anti-HIV drugs to the mother during the
second and third trimesters of pregnancy and to the infant for the first 6 weeks of life have reduced the
rate of mother-to-child transmission of HIV to about 1% in the United States and Europe (from over
20%) (Blanche, 2020; Selph et al., 2019). The incidence of perinatal HIV remains at about 1.75 per
100,000 live births in the United States. Over two-thirds of the HIV-infected children born from 2002–
2013 were to Black or African American mothers (63%) and about 18% to Hispanic or Latina mothers
(Taylor et al., 2017). A combination of socioeconomic factors influences these health disparities, such as
lack of health insurance, limited health literacy, and poverty and associated sense of powerlessness,
which may prevent women from seeking assistance. HIV medications and treatment are expensive, and
an HIV diagnosis is often stigmatizing and may alienate individuals from their communities. Aggressive
treatment may further reduce the transmission of HIV to newborns, and research suggests that it may
even induce remission (Blanche, 2020; Rainwater-Lovett et al., 2015). Women of color and those in
poverty are less likely to receive HIV treatment.
Mother-to-child transmission of HIV has declined as scientists have learned
more about HIV. However, it remains a worldwide problem especially in
developing nations where cultural, economic, and hygienic reasons prevent
mothers from seeking alternatives to breastfeeding, a primary cause of
mother-to-child transmission of HIV.
iStock/alex_skp
Worldwide, HIV rates are highest for infants in developing countries where interventions are widely
unavailable. Globally, 20% to 30% of neonates with HIV develop AIDS during the first year of life and
most die in infancy (United Nations Children’s Fund, 2013). About 80% of children living with HIV reside
in Sub-Saharan African countries (Kassa, 2018). Breastfeeding accounts for 30% to 50% of HIV
transmission in newborns (Sullivan, 2003; World Health Organization, 2011). The World Health
Organization (2010) recommends providing women who test positive for HIV with information about
how HIV may be transmitted to their infants and counseling them not to breastfeed. Yet cultural,
economic, and hygienic reasons often prevent mothers in developing nations from seeking alternatives
to breastfeeding. The widespread lack of clean water in some countries makes the use of powdered
formulas dangerous. Also, in some cultures, women who do not breastfeed may be ostracized from the
community (Sullivan, 2003). Balancing cultural values with medical needs is a challenge.
Environmental Hazards
Prenatal exposure to chemicals, radiation, air pollution, and extremes of heat and humidity can impair
development. Infants prenatally exposed to heavy metals, such as lead and mercury, whether through
ingestion or inhalation, score lower on tests of cognitive ability and intelligence, as well as have higher
rates of childhood illness (Sadler, 2018; Vigeh et al., 2014; Xie et al., 2013). Exposure to radiation can
cause genetic mutations. Infants born to mothers pregnant during the atomic bomb explosions in
Hiroshima and Nagasaki and after the nuclear power accident at Chernobyl displayed many physical
deformities, mutations, and intellectual deficits. Prenatal exposure to radiation is associated with Down
syndrome, reduced head circumference, intellectual disability, reduced cognitive and school
performance, and heightened risk for cancer from childhood through adulthood (Black et al., 2019;
Chang et al., 2014). About 85% of the world’s birth defects occur in developing countries, supporting the
role of context in influencing prenatal development directly via environmental hazards but also indirectly
through the opportunities and resources for education, health, and financial support (Weinhold, 2009).
Prenatal exposure to radiation increases genetic mutation, leading to
impaired development. After the nuclear power accident at Chernobyl, a
significant rise in congenital conditions, or birth defects, was reported.
Sean Gallup/Staff/Getty Images
Contextual Factors and Teratogens
Our discussion of teratogens thus far has examined the effects of each teratogen independently, which
is somewhat misleading because infants are often exposed to multiple teratogens. Most infants exposed
to opioids or cocaine were also exposed to other substances with teratogenic effects, including tobacco,
alcohol, and marijuana, making it difficult to isolate the effect of each drug on prenatal development.
Mothers who use two substances, such as opioids and marijuana, are more likely to give birth to
premature and low-birthweight infants than are those who use one, such as opioids alone (Stein et al.,
2020).
An intersectional perspective illustrates the ways that race and ethnicity, maternal age, socioeconomic
status, and region influence the outcomes of prenatal substance use for women and their infants. Many
U.S. states treat maternal substance use as fetal abuse and construct laws that threaten women who use
substances with involuntary treatment or protective custody during pregnancy (Atkins & Durrance, 2020;
Seiler, 2016). About one-half of U.S. states classify controlled substance use during pregnancy as child
abuse and one-half of U.S. states require that substance use by pregnant mothers be reported to child
protective services, which may lead to removing the newborn from parental custody or even terminating
parental rights altogether (Guttmacher Institute, 2020). In some cases, these consequences have been
extended to include alcohol abuse and dependence (Paltrow & Flavin, 2013; Seiler, 2016). As of 2020, 36
states had laws related to reporting of alcohol consumption during pregnancy (Alcohol Policy
Information System, 2020).
Policies criminalizing maternal substance use discriminate against women of color and those in low
socioeconomic status brackets because low-income African American and Hispanic women are
disproportionately tested and reported to child protective services for substance use (Paltrow & Flavin,
2013). For example, a study of one California county with universal screening policies found that,
although Black and white pregnant women showed similar rates of drug and alcohol use, Black women
were four times more likely than white women to be reported to child protective services after delivery
(Roberts & Nuru-Jeter, 2012). Other recent research confirms that Black and Native American mothers
are more likely to be reported for alcohol use and marijuana than white mothers (Hoerr et al., 2018;
Rebbe et al., 2019a, 2019b).
Criminal sanctions for maternal drug use can discourage women from seeking prenatal and postnatal
care and undermine the physician–patient relationship (American College of Obstetricians and
Gynecologists, 2011; American Medical Association, 2014). Such policies can cause women to develop a
mistrust of medical professionals that ultimately harms their care if they become reluctant to seek
medical care for themselves and their children. One recent study of state policies from 2000–2012 found
that punitive prenatal substance use policies were ineffective because they were not linked with a
reduction in maternal substance abuse exposure at birth (Atkins & Durrance, 2020). Instead, these
policies may deter women from seeking substance use treatment during pregnancy. In contrast, women
who live in states that adopt multiple policies, including treatment and support, are more likely to seek
treatment (Kozhimannil et al., 2019). Fetal outcomes are supported by substance abuse treatment that
rewards abstention, invests in family and community supports, and promotes contact with health care
and social support services (Bada et al., 2012; Hui et al., 2017).
In addition, we must be cautious in interpreting findings about illicit drug use and the effects on
development because the effects of prenatal exposure to drugs are influenced by parenting and other
postnatal (after birth) factors, including poverty, inconsistent parenting, and stress (Lee et al., 2020; Smith
et al., 2016). Parents who abuse substances are more likely to provide poorer quality care, a home
environment less conducive to cognitive development, and parent–child interaction that is less sensitive
and positive than the environments provided by other parents (Hatzis et al., 2017). Quality care can
lessen the long-term impact of prenatal exposure to substances (Beach et al., 2010; Brodie et al., 2019;
Calhoun et al., 2015). When medical and environmental postnatal factors are considered, developmental
differences in substance-exposed infants are reduced and often disappear (Behnke & Smith, 2013).
Disentangling the long-term effects of prenatal exposure to substances, subsequent parenting, and
contextual factors is challenging. Researchers and health care providers who construct interventions
must address the contextual and parenting-related risk factors to improve the developmental outlook
for children exposed to drugs prenatally.
Thinking in Context: Lifespan Development
Consider the influence of teratogens from the perspective of Bronfenbrenner’s bioecological systems
model (Chapter 1). Identify examples of teratogens at each bioecological level: microsystem,
macrosystem, exosystem, and macrosystem. How might this model be used to help promote healthy
prenatal development?
Thinking in Context: Intersectionality
The issue of substance use in pregnant women is complicated. Consider the effects on fetuses and the
rights of pregnant women. How might they conflict? How do issues of justice and equity influence
whether women are likely to be discovered, receive treatment, and/or be charged with maltreatment?
Are all women, regardless of age, ethnicity and race, and SES, equally likely to be discovered and
charged? Why or why not?
Thinking in Context: Applied Developmental Science
Suppose that you plan to study the presence and effects of teratogens on prenatal development.
Choose a teratogen that you believe is most relevant to prenatal health.
1. How might you measure the fetus's or embryo’s exposure to the teratogen? What effects would
you study?
2. To what degree are other teratogens likely to be present? How might this complicate your
results?
3. How will you obtain participants, pregnant women? How might you ensure that your participants
are diverse in terms of race, ethnicity, and socioeconomic status (SES)? Are there other relevant
variables on which women might differ?
4. In what ways might interactions among race, ethnicity, and SES influence your results? Why or
why not?
MATERNAL AND PATERNAL CHARACTERISTICS AND PRENATAL
DEVELOPMENT
LEARNING OBJECTIVE
3.3 Compare the influence of maternal and paternal characteristics on prenatal development.
So far our discussion has focused on the effects of teratogens, external factors on prenatal development.
The developing organism is also influenced by the mother's and biological father’s characteristics.
Maternal Characteristics
A pregnant woman’s characteristics—such as her nutritional status, emotional well-being, and age—may
also influence prenatal outcomes.
Nutrition
Nutrition plays a role in prenatal development both before and after conception. The quality of men’s
and women’s diets influences the health of the sperm and egg (Sinclair & Watkins, 2013). Most women
need to consume 2,200 to 2,900 calories per day (and gain about 25 to 30 pounds in total) to sustain a
healthy pregnancy (Kaiser et al., 2008). Yet about 14.3 million United States households (about 11%)
reported food insecurity in 2018 (United States Department of Agriculture, 2019). That is, at least
sometimes they lacked access to enough food for an active healthy lifestyle for all members of the
household. About 815 million people of the 7.6 billion people in the world, or one in nine, suffer from
chronic undernourishment, almost all of whom live in developing countries (World Under Education
Service, 2018).
Fetal malnutrition is associated with poor growth before and after birth as well as effects that last into
adulthood. Longitudinal studies of infants exposed to prenatal malnutrition during the China Famine
(1959–1961) and the Korean War (1950–1953) revealed long-lasting physical and cognitive effects of
prenatal malnutrition into middle adulthood, including poorer vision, motor and speech disabilities,
cognitive impairment, and increased risk of heart disease, stroke, and diabetes (Han & Hong, 2019; Kim
et al., 2017). Infants who are malnourished can overcome some of the negative effects if they are raised
in enriched environments with adequate food and health care. Most children who are malnourished
before birth remain malnourished; few have the opportunity to be raised in enriched environments after
birth.
Good nutrition is important for a healthy pregnancy.
iStock/becon
In addition to consuming an adequate quantity of calories, healthy prenatal development also requires
consuming a nutritious diet. Inadequate consumption of folic acid (a B vitamin) very early in pregnancy
can result in the formation of neural tube defects stemming from the failure of the neural tube to close.
Spina bifida occurs when the lower part of the neural tube fails to close and spinal nerves begin to grow
outside of the vertebrae, often resulting in paralysis (Avagliano et al., 2019). Spina bifida is often
accompanied by malformations in brain development and impaired cognitive development (Donnan et
al., 2017). Surgery must be performed before or shortly after birth, but lost capacities cannot be restored
(Adzick, 2013; Dewan & Wellons, 2019). Another neural tube defect, anencephaly, occurs when the top
part of the neural tube fails to close and all or part of the brain fails to develop, resulting in death shortly
after birth (Avagliano et al., 2019). Neural tube defects can be prevented by consuming .4 to .8mg of
folic acid. Many foods are fortified with folic acid, but a dietary supplement is safe and ensures that
prenatal needs are met (Bibbins-Domingo et al., 2017). As researchers have learned and disseminated
the knowledge that folic acid helps prevent these defects, the frequency of neural tube defects has
declined to about 1 in 1,000 births (Viswanathan et al., 2017; Williams et al., 2015). However, in a national
study of U.S. mothers, only 24% consumed the recommended dose of folic acid during pregnancy
(Tinker et al., 2010).
Emotional Well-Being
Although stress is inherently part of almost everyone’s life, exposure to chronic and severe stress during
pregnancy, such as by living in unsafe environments, experiencing traumatic life events, and exposure to
racism and discrimination, poses risks for prenatal development, including low birthweight, premature
birth, and a longer postpartum hospital stay (Lima et al., 2018; Schetter & Tanner, 2012). Maternal stress
influences prenatal development in a variety of ways. Emotionally stressed mothers are more likely to
consume a poor diet, potentially harming the fetus (Avalos et al., 2020).
In addition, stress hormones cross the placenta, raising the fetus’s heart rate and activity level. Longterm exposure to stress hormones in utero is associated with higher levels of stress hormones in
newborns and greater release of stress hormones in response to everyday discomfort, such as bathing
(Kapoor et al., 2016; McGowan & Matthews, 2018; Nazzari et al., 2019). As a result, newborns exposed to
prenatal stress tend to be more irritable and may have difficulties in sleep, digestion, and self-regulation
(Davis et al., 2011; Kingston et al., 2012; Matenchuk et al., 2019). In childhood, prenatal stress is
associated with sleep problems, emotional difficulties, behavior problems, and an increased risk for
autism and attention deficit hyperactivity disorder (Hentges et al., 2019; MacKinnon et al., 2018; Manzari
et al., 2019; Okano et al., 2018; Simcock et al., 2019). Prenatal stress may also have epigenetic effects on
development, influencing stress responses throughout the lifespan (DeSocio, 2018; Van den et al., 2017).
Animal research has suggested that the epigenetic effects of prenatal exposure to stress may be
transmitted across generations (Badihian et al., 2019).
Anxiety and depression, collectively known as internalizing problems, are emotional stressors that often
occur with perceived stress. A review of over 70 studies suggests that maternal prenatal anxiety and
depression are associated with emotional problems in infancy, childhood, and adolescence (Madigan et
al., 2018). However, mothers who experience prenatal stress also tend to experience postnatal stress,
making it difficult to disentangle the effects of pre- and postnatal stress on children (Hartman et al.,
2020; Lin et al., 2017). Early mother–infant interactions are influenced by the infant's health and
responses to stress as well as the mother’s mental health (Anderson & Cacola, 2017). Prenatal and
postnatal stress interact to influence children’s outcomes. Children who are exposed to prenatal stress
show greater emotional problems when they are also exposed to postnatal maternal depression and
anxiety as compared with those who are exposed to less maternal postnatal depression (Hartman et al.,
2020).
Some stress during pregnancy is normal, but exposure to chronic and severe
stress during pregnancy poses risks, including low birthweight, premature
birth, and a longer postpartum hospital stay.
iStock/eggeeggjiew
Contextual factors that influence pre- and postnatal maternal depression—such as exposure to poverty,
racism and discrimination, and environmental stressors—are also experienced by children and influence
their development and reactions to stress. Stress in the home may make it difficult for parents to
respond with warmth and sensitivity to an irritable infant or child (Crnic & Ross, 2017). Social support
can mitigate the effects of stress on pregnancy and child care (Feldman et al., 2000; Ghosh et al., 2010).
Although it is clear that stress poses risks to prenatal development, it is difficult to pinpoint its effects on
children and adolescents as they are exposed to multiple biological and contextual influences after birth.
Maternal Age
U.S. women are becoming pregnant at later ages than ever before. Since 1990, the birth rate has
increased for women ages 35 to 39 and 40 to 44, and decreased slightly for women in their 20s
(Hamilton et al., 2017) (Figure 3.4).
Description
Figure 3.4 Birth Rates by Age of Mother, United States 2017
Source: Martin et al. (2018).
Does maternal age matter? The risk of birth complications increases in the late 30s and especially after
age 40. Women who give birth over the age of 40 are at greater risk for pregnancy and birth
complications, including hypertension, gestational diabetes, preterm birth, and miscarriage, than are
younger women (Londero et al., 2019; Magnus et al., 2019; Marozio et al., 2019). These involve increased
risks to the newborn, including low birthweight, preterm birth, respiratory problems, and related
conditions requiring intensive neonatal care (Frederiksen et al., 2018; Grotegut et al., 2014; Kenny et al.,
2013; Khalil et al., 2013). The risk of having a child with Down syndrome also increases sharply with
maternal age, especially after age 40 (Figure 3.5) (Diamandopoulos & Green, 2018; Hazlett et al., 2011).
Description
Figure 3.5 Maternal Age and Down Syndrome
Source: Centers for Disease Control and Prevention (2019a).
Although risks for complications rise linearly with each year (Yaniv et al., 2011), it is important to realize
that the majority of women over age 35 give birth to healthy infants. Differences in context and behavior
may compensate for some of the risks of advanced maternal age. For example, longer use of oral
contraceptives prior to conception is associated with a lower risk of giving birth to a child with Down
syndrome (Horányi et al., 2017; Nagy et al., 2013).
Paternal Characteristics
It is easy to see how mothers’ health, behavior, and contexts influence prenatal development, but what
about biological fathers? It was once thought that biological fathers had no influence on prenatal
development—and therefore research neglected to study their role. Most obviously, fathers influence
the home context. Secondhand smoke from fathers is harmful to the developing organism (Braun et al.,
2020). Fathers’ interactions with pregnant mothers can increase maternal stress, with potential negative
implications for prenatal development, but fathers can also be important sources of social support,
aiding mothers (Glover & Capron, 2017). We know less about how fathers’ health, behaviors, and
contextual factors act as biological influences on prenatal development.
Advanced paternal age is associated with an increased risk of birth defects, chromosomal abnormalities,
and developmental disorders such as Down syndrome and autism spectrum disorder (Brandt et al., 2019;
Day et al., 2016; Herati et al., 2017). Advanced age (over 40) is associated with damage to sperm and
DNA (Rosiak-Gill et al., 2019). Alcohol and substance use and exposure to toxins such as lead can impair
sperm production and quality (Borges et al., 2018; Estill & Krawetz, 2016). Smoking is associated with
DNA damage and mutations in sperm (Beal et al., 2017; Esakky & Moley, 2016).
In addition to DNA, fathers (and mothers) pass on epigenetic markers that can influence their offspring’s
health throughout life and may even be passed to their offspring’s children. Recall from Chapter 1 that
the epigenome determines how DNA is expressed, what genes are turned on and off. The epigenome
contains a molecular record or “memory” of a person’s life experiences, including health behaviors,
exposure to toxins, nutritional status, and more (Abbasi, 2017; Perera et al., 2020). Epigenetic marks are
heritable, passed through ova and sperm, meaning that they can be inherited from parents or even
grandparents (Immler, 2018). Exposure to substances and contaminants can alter the epigenome that is
passed to offspring and potentially from generation to generation (Bošković & Rando, 2018). In one
study, men whose fathers smoked when they were conceived had a 50% lower sperm count than the
men of nonsmoking fathers (Axelsson et al., 2018). However, it is important to remember that the
epigenetic marks we are born with are not set in stone. Some epigenetic marks can be changed after
birth through experiences, health care, and behaviors, such as diet and exercise (Champagne, 2018).
Thinking in Context: Lifespan Development
1. The developing person is influenced by maternal and paternal behaviors and characteristics, such
as age, health, and well-being. What role might contextual factors, including relationships, home,
community, and socioeconomic status, have in determining parental behavior and its impact on the
embryo or fetus?
2. To what degree do the influence of maternal and paternal characteristics illustrate nature
(biology) or nurture (environment)? Explain your reasoning.
CONTEXTUAL AND CULTURAL INFLUENCES ON PRENATAL CARE
LEARNING OBJECTIVE
3.4 Identify barriers to prenatal care and intersectional influences on access to prenatal care.
Prenatal care, a set of services provided to improve pregnancy outcomes and engage the expectant
mother, family members, and friends in health care decisions, is critical for the health of both mother
and infant. Prenatal care visits typically include a physical exam, weight check, and diagnostic procedures
to assess the fetus’s health. Depending on the stage of the pregnancy, prenatal care may include blood
tests and imaging tests, such as ultrasound exams. These visits also provide women the opportunity to
ask questions and for the service provider to provide health care information and advice about nutrition,
prenatal care, and preparing for birth. Women may choose to include their partner, family members, or
friends in these visits. Unfortunately, not all women obtain early prenatal care.
Barriers to Prenatal Care
About one-quarter of pregnant women in the United States do not obtain prenatal care until after the
first trimester; 6% obtain prenatal care at the end of pregnancy or not at all (U.S. Department of Health
and Human Services, 2014). Inadequate prenatal care is a risk factor for low-birthweight and preterm
births as well as infant mortality during the first year (Partridge et al., 2012; Xaverius et al., 2016). In
addition, use of prenatal care predicts the use of pediatric care, and thereby health and development,
throughout childhood (Deaton et al., 2017).
Why do women delay or avoid seeking prenatal care? A common reason is the lack of health insurance
(Baer et al., 2018). Although government-sponsored health care is available for the poorest mothers,
many low-income mothers do not qualify for care or lack information on how to take advantage of care
that may be available. Figure 3.6 lists other barriers to obtaining prenatal care, including difficulty in
finding a doctor, lack of transportation, demands of caring for young children, depression, lack of
education about the importance of prenatal care, lack of social support, poor prior experiences in the
health care system, and family crises (Daniels, Noe, & Mayberry, 2006; Heaman et al., 2015; Mazul et al.,
2016). Black and Latina women report nearly twice as many barriers to accessing care than white women
because they are more likely to experience multiple barriers to care (Fryer et al., 2020).
Description
Figure 3.6 Reasons for Delayed Prenatal Care Among Women, 2009–2010
Source: U.S. Department of Health and Human Services.
Race, Ethnicity, and Prenatal Care
There are significant ethnic and socioeconomic disparities in prenatal care. As shown in Figure 3.7,
prenatal care is closely linked with maternal education (Blakeney et al., 2019). About 86% of women with
a college degree obtain first-trimester care, compared with less than two-thirds of women with less than
a high school diploma (U.S. Department of Health and Human Services, 2014).
Description
Figure 3.7 Timing of Prenatal Care Initiation by Maternal Education, 2012
Source: U.S. Department of Health and Human Services.
In addition, women of color are disproportionately less likely to receive prenatal care during the first
trimester and are more likely to receive care beginning in the third trimester or no care (Blakeney et al.,
2019). In 2018, Native Hawaiian and Native American women were least likely to obtain prenatal care
during the first trimester, followed by Black, Hispanic, and Asian American and white American women
(Hamilton et al., 2018) (Figure 3.8). In the most extreme case, only about half of Native Hawaiian or other
Pacific Islander women obtain first-trimester care, and one in five obtains late or no prenatal care. Ethnic
differences are thought to be largely influenced by socioeconomic factors, as the ethnic groups least
likely to seek early prenatal care are also the most economically disadvantaged members of society and
are most likely to live in communities with fewer health resources, including access to physicians and
hospitals, sources of health information, and nutrition and other resources.
Description
Figure 3.8 First-Trimester and Late-Prenatal Care by Race and Ethnicity, 2018
Source: Hamilton et al. (2018).
Although prenatal care predicts better birth outcomes, cultural factors also appear to protect some
women and infants from the negative consequences of inadequate prenatal care. In a phenomenon
termed the
, Latina mothers, despite low rates of prenatal care, tend to experience rates
of low birthweight and mortality below national averages. These favorable birth outcomes are striking
because of the strong and consistent association between socioeconomic status and birth outcomes and
because Latinos as a group are among the most socioeconomically disadvantaged ethnic populations in
the United States (McGlade et al., 2004; Ruiz et al., 2016).
Latina paradox
Several factors are thought to account for the Latina paradox, including strong cultural support for
maternity, healthy traditional dietary practices, and the norm of selfless devotion to the maternal role
(known as
) (Fracasso & Busch-Rossnagel, 1992; McGlade et al., 2004). These protective
cultural factors interact with strong social support networks and informal systems of health care among
Latina women, in which women tend to take responsibility for the health needs of those beyond their
nuclear households. Mothers benefit from the support of other family members such as sisters, aunts,
and other extended family. In this way, knowledge about health is passed down from generation to
generation. There is a strong tradition of women helping other women in the community, and warm
interpersonal relationships, known as
, are highly valued (Fracasso & Busch-Rossnagel,
1992; McGlade et al., 2004).
marianismo
personalismo
These cultural factors are thought to underlie the positive birth outcomes seen in Latina women, yet
they appear to erode as Latina women acculturate to American society. The birth advantage has been
found to decline in subsequent American-born generations. Recent findings have called the existence of
the Latina paradox into question, as some samples have illustrated that the negative effects of
socioeconomic disadvantage cannot be easily ameliorated by cultural supports (Hoggatt et al., 2012;
Sanchez-Vaznaugh et al., 2016). Other work has suggested that the Latina paradox is more complex. One
recent study of Puerto Rican women found that women with bicultural acculturation, who identify with
both Latina and continental U.S. cultures, experience lower stress levels than those with low
acculturation (Chasan-Taber et al., 2020). Women’s sense of identity may play a role in their perceived
stress and perhaps ultimately the health of their pregnancy.
Latina women show positive prenatal outcomes despite low rates of prenatal
care and membership in a marginalized group. The Latina paradox is
influenced by social support and cultural valuing of the maternal role.
Courtney Hale/Getty Images
The mixed findings regarding the Latina paradox may also be influenced by complex intersecting social
factors, such as geography and politics. Latina women who live on the U.S.–Mexico border are much
more likely to have a cesarean birth than those who do not live on the border. This strip of land spans
2,000 miles and four states (Morris et al., 2018). Hot political debates center around this strip, including
debates about immigration, poverty, crime, and whether to construct a physical barrier—a wall—to
distinguish each country. The intersecting social disadvantages for Latina women who live on the border
may pose multiple threats to their health and the health of their fetuses.
Thinking in Context: Intersectionality
1. What are some examples of barriers to receiving prenatal care? In what ways do factors such as
race, ethnicity, socioeconomic status, and culture influence whether women receive prenatal care?
2. Would you expect all women—white, Asian American, Black, Hispanic, and Native American—to
experience and perceive similar barriers? Why or why not? What environmental factors might
contribute to women's different experiences and perceptions?
Thinking in Context: Lifespan Development
How might contextual factors influence the Latina paradox? From a bioecological systems perspective,
what macrosystem factors may contribute to this phenomenon? Identify exosystem factors in the
community and extended environment that might influence Latinas’ pregnancies and birth outcomes?
What role might microsystem factors play? How might you expect these bioecological factors and their
interactions to change over time (chronosystem)?
CHILDBIRTH
LEARNING OBJECTIVE
3.5 Summarize birth options and the process of childbirth.
At about 40 weeks of pregnancy, or 38 weeks after conception, childbirth, also known as labor, begins.
Labor
Labor progresses in three stages. The first stage of labor, dilation, is the longest. It typically lasts 8 to 14
hours for a woman having her first child; for later-born children, the average is 3 to 8 hours. Labor
begins when the mother experiences regular uterine contractions spaced at 10- to 15-minute intervals.
Initial contractions may feel like a backache or menstrual cramps or may be extremely sharp. The
amniotic sac, a membrane containing the fetus surrounded by fluid, may rupture at any time during this
stage, often referred to as the “water breaking.” The contractions, which gradually become stronger and
closer together, cause the cervix to dilate so that the fetus’s head can pass through, as shown in Figure
3.9.
Description
Figure 3.9 Stages of Labor
Source: Adapted from Gerard J. Tortora and Bryan H. Derrickson (2009).
The second stage of labor, delivery, begins when the cervix is fully dilated to 10 cm and the fetus’s head
is positioned at the opening of the cervix—known as “crowning.” It ends when the baby emerges
completely from the mother’s body. It is during this stage that the mother typically feels an urge to push
or bear down with each contraction to assist the birth process. Delivery can take from 30 minutes to an
hour and a half.
In the third stage of labor, the placenta separates from the uterine wall and is expelled by uterine
contractions. This typically happens about 5 to 15 minutes after the baby has emerged, and the process
can take up to a half hour.
Medication During Delivery
Medication is administered in over 80% of births in the United States (Declercq et al., 2014). Several
drugs are used during labor, with varying effects.
, such as tranquilizers, reduce the perception
of pain. They may be used in small doses to relieve pain and to help the mother relax. However, these
drugs pass through the placenta to the fetus and are associated with decreases in heart rate and
respiration (Hacker et al., 2016). Newborns exposed to some medications show signs of sedation and
difficulty regulating their temperature (Gabbe et al., 2016).
are painkillers that block overall
sensations or feelings. General anesthesia (getting “knocked out”) blocks consciousness entirely; it is no
longer used because it is transmitted to the fetus and can slow labor and harm the fetus. Today, the
most common anesthetic is an epidural, in which a pain-relieving drug is administered to a small space
between the vertebrae of the lower spine, numbing the woman’s lower body. There are several types of
epidurals, with varying numbing effects ranging from immobilizing the lower body to numbing only the
pelvic region, enabling the mother to move about (a so-called walking epidural). Epidurals are
associated with a longer delivery as they weaken uterine contractions and may increase the risk of a
cesarean section, as discussed next (Gabbe et al., 2016; Herrera-Gómez et al., 2017). An analysis of nearly
15,500 deliveries suggested that newborns exposed to epidural anesthesia did not differ from those
exposed to no anesthesia (Wang et al., 2018). The American College of Obstetricians and Gynecologists
(2017) has concluded that the proper administration of medication poses few risks to the newborn and
pain medication should be available to all women.
Analgesics
Anesthetics
Cesarean Delivery
Sometimes a vaginal birth is not possible because of concerns for the health or safety of the mother or
fetus. Normally the baby’s head is the first part of the body to exit the vagina. A baby facing feet-first is
said to be in a breech position, which poses risks to the health of the baby. Sometimes the obstetrician
can turn the baby so that it is head-first. In other cases, a cesarean section, or C-section, is common. A
cesarean section is a surgical procedure that removes the fetus from the uterus through the abdomen.
About 32% of U.S. births were by cesarean section in 2018 (Hamilton et al., 2018; Martin et al., 2018).
Cesarean sections are performed when labor progresses too slowly, the fetus is in breech position or
transverse position (crosswise in the uterus), the head is too large to pass through the pelvis, or the fetus
or mother is in danger (Jha et al., 2015; Visscher & Narendran, 2014). Babies delivered by cesarean are
exposed to more maternal medication and secrete lower levels of the stress hormones that occur with
vaginal birth that are needed to facilitate respiration, enhance circulation of blood to the brain, and help
the infant adapt to the world outside of the womb. Interactions between mothers and infants, however,
are similar for infants delivered vaginally and by cesarean section (Durik et al., 2000).
A cesarean section is a surgical procedure that removes the fetus from the
uterus through the abdomen.
Pacific Press/Sipa USA/Newscom
Natural Childbirth
Natural childbirth is an approach to birth that reduces pain through the use of breathing and relaxation
exercises. Natural childbirth methods emphasize preparation by educating mothers and their partners
about childbirth, helping them reduce their fear, and teaching them pain management techniques.
Although most women use at least some medication in childbirth, many women adopt some natural
childbirth methods.
The most widely known natural childbirth method—the Lamaze method—was created by a French
obstetrician, Ferdinand Lamaze (1956). The Lamaze method entails teaching pregnant women about
their bodies, including detailed anatomical information, with the intent of reducing anxiety and fear.
When women know what to expect and learn a breathing technique to help them relax, they are better
able to manage the pain of childbirth. The Lamaze method relies on the spouse or partner as coach,
providing physical and emotional support and reminding her to use the breathing techniques.
In addition to the expectant mother’s partner, a doula can be an important source of support. A doula is
a caregiver who provides support to an expectant mother and her partner throughout the birth process
(Kang, 2014). Doulas provide education about anatomy, delivery, and pain management practices, such
as breathing. The doula is present during birth, whether at a hospital or other setting, and helps the
woman carry out her birth plans. The presence of a doula is associated with less pain medication, fewer
cesarean deliveries, and higher rates of satisfaction in new mothers (Gabbe et al., 2016; Kozhimannil et
al., 2016).
Home Birth
Although common in nonindustrialized nations, home birth is rare, comprising 1.5% of all births in 2016
in the United States (MacDorman & Declercq, 2016). The remaining 98.5% of births occur in hospitals.
Most home births are managed by a midwife, a health care professional, usually a nurse, who specializes
in childbirth. Midwives provide health care throughout pregnancy and supervise home births. One
review of 50 studies found that the use of midwives, whether as part of a home birthing plan or as part
of a plan to birth in a hospital setting, is associated with reduced neonatal mortality, reduced preterm
birth, fewer interventions, and more efficient use of medical resources (Renfrew et al., 2014).
Is a home birth safe? A healthy woman, who has received prenatal care and is not carrying twins, is
unlikely to encounter problems requiring intervention—and may be a good candidate for a home birth
(Wilbur et al., 2015). Although unpredictable events can occur and immediate access to medical facilities
can improve outcomes, studies from Europe indicate that home birth is not associated with greater risk
of perinatal mortality. Home birth is far more common in many European countries than in the United
States (20% in the Netherlands, 8% in the United Kingdom, and about 1.5% in the United States)
(Brocklehurst et al., 2011; de Jonge et al., 2015). The few U.S. studies that have examined planned home
birth compared with hospital birth have found no difference in neonatal deaths or Apgar scores (a
measure of newborn health, discussed later in this chapter), and women who have a planned home birth
report high rates of satisfaction (Jouhki et al., 2017; Zielinski et al., 2015).
Cultural Differences in Childbirth
Societies vary in their customs and perceptions of childbirth, including the privacy afforded to giving
birth and how newborns are integrated into the community. In the United States, birth is a private event
that usually occurs in a hospital, attended by medical personnel and one or two family members. In most
cases, the first-time mother has never witnessed a birth but is well educated and may have wellinformed expectations. After birth, the mother and infant are often visited by family within designated
hospital visiting hours; the newborn usually rooms with the mother all or part of the day.
In a small village in southern Italy, birth is a community event. It usually takes place in a hospital,
attended by a midwife (Fogel, 2007; Schreiber, 1977). Just after birth, the midwife brings the mother’s
entire family (immediate and extended) to the mother’s room and they take turns congratulating the
mother and baby, kissing them. The family provides a party, including pastry and liqueurs. During labor
and afterward, the mother is supported and visited by many of her friends and relatives to recognize the
contribution that the mother has made to the community. The mother-in-law is an example of the social
support system in place, because a few days before and until about 1 month after the birth she brings
and feeds the mother ritual foods of broth, marsala, and fresh cheeses.
In some other cultures, birth is an even more public process. The Jahara of South America give birth
under a shelter in full view of everyone in the village (Fogel, 2007). On the Indonesian island of Bali, it is
assumed that the husband, children, and other family will want to be present. The birth occurs in the
home with the aid of a midwife and female relatives. As a result, Balinese women know what to expect in
giving birth to their first child because they have been present at many births (Diener, 2000). Babies are
immediately integrated into the family and community as they are considered a reincarnated soul of an
ancestor. Many kin are present to support the mother and baby since the child is considered to be
related to many more people than its parents.
A midwife prepares a mother to give birth in her home. Birth practices vary
by culture.
Viviane Moos/Getty Images
Childbirth is tied to social status in the Brong-Ahafo region in Ghana. After a delivery, women achieve a
higher social position and can then give advice to other women (Jansen, 2006). Home deliveries are
highly valued. The more difficult the delivery and the less skilled assistance she receives, the more
respect a woman attains, the higher her position will be, and the more influence she has on the
childbirth decisions of other women, such as whether to give birth at home or in a medical setting and
how to combine traditional and modern practices (Bazzano et al., 2008).
Many cultures conduct rites that they believe protect newborns from evil and spirits. Among the Maya of
the Yucatan region of Mexico, there are few changes in the expectant mother’s surroundings; the Mayan
woman lies in the same hammock in which she sleeps each night. The father-to-be is expected to be
present during labor and birth to take an active role but also to witness the suffering that accompanies
labor. If the father is not present and the child is stillborn, it is blamed on the father’s absence. The
pregnant woman’s mother is present, often in the company of other females, including sisters, sisters-inlaw, mothers-in-law, godmothers, and sometimes neighbors and close friends. The mother and child
must remain inside the house for 1 week before returning to normal activity after birth because it is
believed that the mother and newborn are susceptible to the influence of evil spirits from the bush
(Gardiner & Kosmitzki, 2018).
A neighboring ethnic group, the Zinacanteco, place their newborns naked before a fire. The midwife
who assisted the mother says prayers asking the gods to look kindly upon the infant. The infant is
dressed in a long skirt made of heavy fabric extending beyond the feet; this garment is to be worn
throughout the first year. The newborn is then wrapped in several layers of blankets, even covering the
face, to protect against losing parts of the soul. These traditional practices are believed to protect the
infant from illnesses as well as evil spirits (Brazelton, 1977; Fogel, 2007). Cultures vary in their specific
practices but all offer support to the mother during childbirth.
Thinking in Context: Lifespan Development
1. Why do you think there are cultural differences in birth practices? What kinds of factors might
underlie the differences we observe? Relatedly, how might cultural and contextual factors influence
the rates of home birth, natural birth, and cesarean birth?
2. Ask adults of different generations, perhaps a parent or an aunt and a grandparent or family
friend, about their birth experiences. How do these recollections compare with current birthing
practices?
Thinking in Context: Applied Developmental Science
Create a birth plan for a healthy woman in her 20s. What type of birth will you choose? Why? How might
you address pain relief? Consider a healthy 39-year-old woman; in what ways might your birth plan
change (or not)? Why?
LOW-BIRTHWEIGHT INFANTS: PRETERM AND SMALL-FOR-DATE BABIES
LEARNING OBJECTIVE
3.6 Examine risks for low birthweight, characteristics of low-birthweight infants, and ways of
supporting positive outcomes of low-birthweight infants.
About 8% of infants born in the United States each year are low birthweight (Martin et al., 2018). Infants
are classified as low birthweight when they weigh less than 2,500 grams (5.5 pounds) at birth; very low
birthweight refers to a weight less than 1,500 grams (3.5 pounds), and extremely low birthweight refers
to a weight less than 750 grams (1 lb., 10 oz.). Low-birthweight (LBW) infants may be preterm,
premature (born before their due date), or small for date, who are full-term but have experienced slow
growth and are smaller than expected for their gestational age. Infants who are born with low
birthweight are at risk for a variety of developmental difficulties. Indeed, their very survival is far from
certain. Low birthweight is the second leading cause of infant mortality (Mathews & MacDorman, 2013;
Murphy et al., 2018). Infants most at risk for developmental challenges, handicaps, and difficulty
surviving are those with extremely low birthweight.
Contextual Risks for LBW
Socioeconomic disadvantage interacts with race and ethnicity in complex ways to influence LBW in the
United States (Figure 3.10). In 2016, non-Hispanic Black infants were more than twice as likely to be born
low birthweight (11%) than non-Hispanic white and Hispanic infants (5% and 6%, respectively) (Womack
et al., 2018). SES plays a role in these differences, but it is not the whole story. In one study, LBW rates
were higher in non-Hispanic Black mothers than non-Hispanic white mothers; the racial difference
declined (but did not disappear) when the researchers took into account financial and relationship
stresses, suggesting a role for SES in racial differences, but also other factors (Almeida et al., 2018). In
another study of over 10,000 Californian women, the most economically disadvantaged Black and white
women showed similar LBW rates, but increases in income were more strongly associated with
improvement in LBW rates among white than Black women (Braveman et al., 2015). As SES advantage
increased for both white and Black women, the racial disparity in LBW outcomes grew. Racial differences
in LBW are not a function only of income but by other factors, such as the experience of racism and
discrimination (Ncube et al., 2016; Ramraj et al., 2020).
Description
Figure 3.10 Gestational Age and Birthweight, by Race and Ethnicity: United
States, 2018
Sources: Centers for Disease Control and Prevention; National Center for
Health Statistics.
In the United States, socioeconomic status is associated not simply with income but with access to social
services, such as health care, that can determine birth outcomes. In one international comparison of U.S.
births with those in the UK, Canada, and Australia—countries with health care and social services
available to all individuals—the most disadvantaged women in all four countries were more likely to give
birth to LBW infants, but SES was most strongly linked with LBW in the United States, where health care
is privatized (Martinson & Reichman, 2016). A recent comparison among five North American cities
(Baltimore, Boston, Chicago, Philadelphia, and Toronto, Canada) illustrates the intersection of race and
access to health care in birth outcomes (De Maio et al., 2018). In this study, unemployment and living in
a racial or ethnically segregated community was not associated with LBW in Toronto, Canada (where
health care is readily available to all), but they were strongly associated with LBW across communities in
the four U.S. cities analyzed, where low socioeconomic people often lack health care. Although this study
pointed to the role of health care access in birth outcomes, Black women may have different racial
experiences in Canada and the United States. Differences in discrimination, racism, and perceived stress
may also play a role in these differing birth outcomes.
Characteristics of LBW Infants
Low-birthweight infants are at a disadvantage when it comes to adapting to the world outside the
womb. At birth, they often experience difficulty breathing and are likely to suffer from respiratory
distress syndrome, in which the newborn breathes irregularly and at times may stop breathing (Charles
et al., 2018). Low-birthweight infants have difficulty maintaining homeostasis, a balance in their
biological functioning. Their survival depends on care in neonatal hospital units, where they are confined
in isolettes that separate them from the world, regulating their body temperature, aiding their breathing
with the use of respirators, and protecting them from infection. Many low-birthweight infants cannot yet
suck from a bottle and are fed intravenously.
The deficits that LBW infants endure range from mild to severe and correspond closely to the infant’s
birthweight, with extremely low-birthweight infants suffering the greatest problems (Hutchinson et al.,
2013). LBW infants are at higher risk for poor growth, cerebral palsy, seizure disorders, neurological
difficulties, respiratory problems, and illness (Adams-Chapman et al., 2013; Charles et al., 2018; Durkin et
al., 2016; Miller et al., 2016). Low-birthweight children often experience difficulty in self-regulation and
cognitive problems that may persist into adulthood (Eryigit Madzwamuse et al., 2015; Hutchinson et al.,
2013; MacKay et al., 2010).
As children and adolescents, they are more likely to show problems with inattention, hyperactivity, and
experience emotional and behavioral problems, which makes it difficult to interact and respond to
stimulation appropriately (Franz et al., 2018; Jaekel et al., 2018; Mathewson et al., 2017). They tend to
show poor social competence and poor peer relationships, including peer rejection and victimization in
adolescence (Georgsdottir et al., 2013; Ritchie et al., 2015; Yau et al., 2013). As adults, LBW individuals
tend to be less socially engaged, show poor communication skills, have social difficulties, and may score
high on measures of anxiety (Eryigit Madzwamuse et al., 2015; Mathewson et al., 2017).
Low birthweight infants require extensive care. They are at risk for poor
developmental outcomes and even death.
AFP Contributor/Contributor/Getty
Not only are LBW infants at a physical disadvantage, but they often begin life at an emotional
disadvantage because they are at risk for experiencing difficulties in their relationships with their
parents. Parenting a LBW infant is stressful even in the best of circumstances (Howe et al., 2014). Such
infants tend to be easily overwhelmed by stimulation and difficult to soothe (Gardon et al., 2019). Often,
LBW infants are ill-equipped to interact with parents. They are slow to initiate social interactions and do
not attend to caregivers, looking away or otherwise resisting attempts to attract their attention
(Eckerman et al., 1999; Provasi, 2019). Because low-birthweight infants often do not respond to attempts
to solicit interaction, they can be frustrating to interact with, can be difficult to soothe, and are at risk for
less secure attachment to their parents (Jean & Stack, 2012; Wolke et al., 2014). Research also indicates
that they may experience higher rates of child abuse, partly because of their special needs but also
because the risk factors for low birthweight, such as prenatal exposure to substances or maternal illness,
also pose challenges for postnatal survival—and themselves are associated with abuse (Cicchetti & Toth,
2015; Puls et al., 2019). Indeed, low socioeconomic status, a risk factor for LBW, may accentuate the
childhood cognitive and socioemotional outcomes associated with LBW (Hines et al., 2020).
Promoting Positive Outcomes of LBW Infants
Parental responses to having a low-birthweight infant influence the child’s long-term health outcomes,
independently of perinatal risk, suggesting that the parenting context is an important influence on infant
health (Pierrehumbert et al., 2003; Provasi, 2019). When mothers have knowledge about child
development and how to foster healthy development, are involved with their children, and create a
stimulating home environment, low-birthweight infants tend to have good long-term outcomes
(Benasich & Brooks-Gunn, 1996; Jones et al., 2009; Lynch & Gibbs, 2017). A study of low-birthweight
children showed that those who experienced sensitive parenting showed faster improvements in
executive function and were indistinguishable from their normal-weight peers by age 5; however, those
who experienced below-average levels of sensitive parenting showed lasting deficits (Camerota et al.,
2015).
In terms of weight, exposure to sensitive, positive parenting predicted LBW children’s catching up to
their normal-birthweight peers at age 8 in academic achievement, but exposure to insensitive parenting
predicted much poorer functioning (Jaekel et al., 2015). Longitudinal research has found that lowbirthweight children raised in unstable, economically disadvantaged families tend to remain smaller in
stature, experience more emotional problems, and show more long-term deficits in intelligence and
academic performance than do those raised in more advantaged homes (Taylor et al., 2001).
Interventions to promote the development of low-birthweight children often emphasize helping parents
learn coping strategies for interacting with their infants and managing parenting stress (Chang et al.,
2015; Lau & Morse, 2003). Interventions focused on teaching parents how to massage and touch their
infants in therapeutic ways as well as increase skin-to-skin contact with their infants are associated with
better cognitive and neurodevelopmental outcomes at age 2 (Procianoy et al., 2010).
One intervention common in developing countries where mothers may not have access to hospitals is
kangaroo care, in which the infant is placed vertically against the parent’s chest, under the shirt,
providing skin-to-skin contact (Charpak et al., 2005). As the parent goes about daily activities, the infant
remains warm and close, hears the voice and heartbeat, smells the body, and feels constant skin-to-skin
contact. Kangaroo care is so effective that the majority of hospitals in the United States offer kangaroo
care to preterm infants. Babies who receive early and consistent kangaroo care grow more quickly, sleep
better, score higher on measures of health, and show more cognitive gains throughout the first year of
life (Boundy et al., 2016; Jefferies, 2012; Sharma et al., 2019)—more breastfeed, too.
Thinking in Context: Lifespan Development
1. A basic tenet of development is that individuals are active in their development, influencing the
world around them (Chapter 1). Consider low-birthweight (LBW) infants: How might their
characteristics and abilities influence their caregivers? Why is caring for LBW infants challenging?
2. Parental responses to having a low-birthweight infant influence the child’s long-term health
outcome. How might contextual factors influence parents’ responses? What supports from the
family, community, and broader society can aid parents in helping their low-birthweight infants
adapt and develop healthily?
THE NEWBORN
LEARNING OBJECTIVE
3.7 Discuss the neonate’s physical capacities.
The average newborn is about 20 inches long and weighs about 7½ pounds. Boys tend to be slightly
longer and heavier than girls. Newborns have distinctive features, including a large head (about ¼ of
body length) that is often long and misshapen from passing through the birth canal. The newborn’s skull
bones are not yet fused—and will not be until about 18 months of age—permitting the bones to move
and the head to mold to the birth canal, easing its passage. Given this, the newborn’s head may appear
misshapen at birth. A healthy newborn is red-skinned and wrinkly at birth; skin that is bluish in color
indicates that the newborn has experienced oxygen deprivation. Some babies emerge covered with
, the fuzzy hair that protects the skin in the womb; for other babies, the lanugo falls off prior to
birth. The newborn’s body is covered with
, a white waxy substance that protects against
infection; this dries up within the first few days. Although many hospital staff wash the vernix caseosa
away after birth, research suggests that it is a naturally occurring barrier to infection and should be
retained at birth (Jha et al., 2015; Nishijima et al., 2019).
lanugo
vernix caseosa
Medical and Behavioral Assessment of Newborns
After birth, newborns are routinely screened with the Apgar scale, which provides a quick and easy
overall assessment of the baby’s immediate health. As shown in Table 3.1, the Apgar scale is composed
of five subtests: appearance (color), pulse (heart rate), grimace (reflex irritability), activity (muscle tone),
and respiration (breathing). The newborn is rated 0, 1, or 2 on each subscale for a maximum total score
of 10. A score of 4 or lower means that the newborn is in serious condition and requires immediate
medical attention. The rating is conducted twice, 1 minute after delivery and again 5 minutes after birth;
this timing ensures that hospital staff will monitor the newborn over several minutes. A low Apgar score
is associated with an increased risk of neonatal death, but an increase in score from 5 to 10 minutes is
associated with lower risk (Cnattingius et al., 2020). Over 98% of all newborns in the United States
achieve a 5-minute score of 7 to 10, indicating good health (Martin et al., 2013).
Table 3.1 Apgar Scale
Rating (Absence–Presence)
Indicator
0
1
Appearance (color)
Blue
Pink body, blue extremities
Pulse (heart rate)
Absent
Slow (below 100)
Grimace (reflex irritability) No response Grimace
Activity (muscle tone)
Limp
Weak and inactive
Respiration (breathing)
Absent
Irregular and slow
2
Pink
Rapid (over 100)
Coughing, crying
Active and strong
Crying, good
Source: Adapted from Apgar (1953).
The Brazelton Neonatal Behavioral Assessment Scale (NBAS) is a neurobehavioral assessment
commonly administered to newborns, especially those who are judged to be at risk (Bartram et al.,
2015). It is administered in the first few days after birth to assess the newborn’s neurological
competence as indicated by the responsiveness to the physical and social environment, perception, and
motor skills such as activity level and the ability to bring a hand to the mouth (Nugent, 2013). The NBAS
also assesses infants’ attention and state changes, including excitability and ability to settle down after
being upset. When parents observe and participate in their baby’s NBAS screening, they learn about
their newborn’s perceptual and behavioral capacities and are better able to elicit gazes, quiet fussiness,
and tend to be more responsive to their infants (Benzies et al., 2013).
The Newborn’s Perceptual Capacities
Until recent decades, it was widely believed that the newborn was perceptually immature—blind and
deaf at birth. Developmental researchers now know that the newborn is more perceptually competent
than ever imagined. Both taste and smell are well developed at birth. Taste appears to function well
before birth because research has shown that fetuses swallow sweetened amniotic fluid more quickly
than bitter fluid (Ventura & Worobey, 2013). Newborns can discriminate smells and calm in response to
the scent of amniotic fluid and other familiar smells (Neshat et al., 2016; Rotstein et al., 2015). The visual
capacities of the newborn are more limited and focused primarily on the near environment. Newborn
vision is blurry and best at about 18 inches away—the typical distance to a parent’s face when holding
the infant.
The most remarkable newborn capacities for perception and learning are auditory in nature. Pregnant
women often report that they notice fetal movements in response to a loud sound like a car horn or a
door slamming. The fetus responds to auditory stimulation as early as 23 to 25 weeks after conception
(Hepper, 2015). By 32 to 34 weeks, the fetus responds to the mother’s voice as indicated by a change in
heart rate (Kisilevsky & Hains, 2011). Prior to birth, the fetus can discriminate voices and speech sounds
(Granier-Deferre et al., 2011) and even language features like prosody (Draganova et al., 2018). At birth,
newborns show preferences for speech sounds, their mother’s voice, their native language, and even
stories and music heard prenatally (Moon et al., 1993). Moreover, from birth, the newborn is an active
listener, paying attention to sounds and naturally taking advantage of opportunities to learn
(Vouloumanos et al., 2010).
Newborn States of Arousal
Newborns display regular cycles of eating, elimination, and states of arousal or degrees of wakefulness.
In a typical day, newborns move in and out of six infant states or levels of arousal, as shown in Table 3.2.
Most newborns spend about 70% of their time sleeping and wake every 2 to 3 hours. These short
stretches of sleep alternate with shorter periods of wakefulness that are primarily devoted to feeding.
During the first month, infants often move rapidly from one state to another, dozing off during feeding.
Naps are punctuated by periods of drowsiness, alert and inalert activity, and crying.
Table 3.2 Newborn States of Arousal
State
Description
Regular
sleep
This is being fully asleep with little or no body movement. The eyes are
closed with no eye movements. The face is relaxed, and breathing is slow
and regular.
Irregular
Facial grimaces, limb movements, occasional stirring, and eye movement
sleep
behind closed lids indicate rapid eye movement (REM) sleep. Breathing is
irregular.
Drowsiness Falling asleep or waking up, eyes open and closed and have a glazed look.
Breathing is even but faster than in regular sleep.
Quiet
The eyes are open and attentive, exploring the world; the body is relatively
alertness
inactive. Breathing is even.
Waking
There are frequent bursts of uncoordinated activity. Breathing is irregular;
activity
the face may be relaxed or tense. Fussiness and crying may occur.
Daily
Duration in
Newborns
8–9 hours
8–9 hours
Varies
2–3 hours
1–4 hours
Sources: Prechtl (1974); Wolff (1966).
Newborn sleep cycles are brief, lasting from 45 minutes to 2 to 3 hours, but similar to those of adults in
that they consist of both REM sleep, or rapid eye movement (REM) sleep, and non-REM sleep
(Korotchikova et al., 2016). When a person is in REM sleep, the brain wave activity is remarkably similar
to that of the waking state. The eyes move back and forth beneath closed lids; heart rate, blood
pressure, and breathing are uneven; and there are slight body movements. It is sleep. Newborns spend
about half of their sleep time in REM, but by ages 3 to 5 children spend about 15% to 20% of their sleep
in REM, similar to adults (Grigg-Damberger & Wolfe, 2017; Kobayashi et al., 2004).
Why do newborns spend so much time in REM sleep? REM sleep is associated with dreaming in both
children and adults. Neonates spend most of their time, about 18 hours, sleeping each day and therefore
spend little time in the active alert state in which they get stimulation from the environment (De Beritto,
2020). REM is a way that the brain stimulates itself, which is important for brain development (GriggDamberger & Wolfe, 2017; Wolfe & Ralls, 2019). This view of REM sleep as serving a self-stimulation
function is supported by findings that fetuses and preterm babies, who are even less able to take
advantage of external stimulation than are newborns, spend even more time in REM sleep. In addition,
neonates with low REM sleep activity tend to score lower on mental tests at 6 months of age (ArditiBabchuk et al., 2009). It is clear that sleep serves an important role in fetal and newborn development.
Thinking in Context: Biological Influences
From the perspective of evolutionary developmental science, newborns are adapted for life. Consider
this in light of what you know about newborns. In what ways might newborns’ shifting states of arousal
be adaptive? Their perceptual abilities?
Thinking in Context: Applied Developmental Science
“Herman is almost always sleeping. When he’s awake, I can’t tell if he even recognizes me,” Jana exclaims
with exhaustion and perhaps disappointment with her newborn son. Do you think that this is true?
Explain the newborn’s perceptual abilities and sleep cycles to Jana.
APPLY YOUR KNOWLEDGE
Best friends since first grade, Charmayne and Latisha were inseparable throughout childhood,
adolescence, and now as adults. Shortly after Charmayne discovered she was pregnant, Latisha revealed
that she too was expecting. Together they learned about their developing babies, brainstormed baby
names, and planned how to fit an infant into their cramped homes.
Charmayne and Latisha also commiserated about the challenges of pregnancy. Charmayne worked as a
nail technician at a busy nail and hair salon. It’s not uncommon for her customers to complain about the
chemical odors, but she usually doesn’t notice the smell. Charmayne’s boss suggests that she wear a
surgical mask and sometimes Charmayne complies, but it’s hard to converse with her customers from
behind a mask. Charmayne has always found it uncomfortable to sit at the manicurist table all day, but
now her rapidly expanding pregnancy “bump” makes sitting and leaning over the table very difficult.
Most days she takes an over-the-counter pain killer to ease the discomfort. In the past, her doctor has
prescribed medical marijuana for her symptoms. Charmayne still has some and consumes it occasionally
when the pain is overpowering. She figures that once in a while can’t hurt—especially if it helps her do
her job. After all, she’s only five months pregnant—the baby has lots of time to develop.
Latisha worked as a server and bartender at a popular local restaurant. She loves her job, but most shifts
leave her exhausted as she’s on her feet all day. One night when she was especially tired she nearly
dropped a heavy tray. Latisha’s boss suggested that she work at the bar instead of serving food. Latisha
happily complied, as she enjoys interacting with customers at the bar. Most of her customers are friendly.
Sometimes regular customers will order alcoholic drinks for a big group of friends and ask her to share
one with them. Sometimes the idea of an alcoholic drink makes her nauseous, but she usually agrees
because happy customers mean big tips and, at four weeks of pregnancy, she’s trying to save money for
the baby growing inside of her. Usually the drink makes her feel better. Most nights Latisha stands
outside during her breaks. She used to smoke during breaks, but she gave up cigarettes when she
learned she was pregnant. Giving up nicotine was difficult, and Latisha missed the habit of smoking, so
she tried vaping instead. Electronic cigarettes don’t give off smoke, so they can’t be that bad, she
reasoned.
One spring morning a several weeks before her due date, Latisha gave birth to a baby girl. She seemed
healthy, but tiny. Charmayne carried her daughter to term, giving birth a few days before her due date.
Several months later, the best friends visited, placing their babies on the floor together for tummy time.
1. Most women are exposed to some teratogens during pregnancy. Generally speaking, what are some
examples of teratogens and other environmental influences on prenatal development?
2. What teratogens and environmental influences on prenatal development did Charmayne and
Latisha encounter?
3. Latisha’s daughter is a low-birthweight infant. What are characteristics of low-birthweight infants,
and what can Latisha expect? How can she best care for her daughter?
4. Suppose that Charmayne and Latisha give birth to full-term newborns, but one had a defect that
was visible at birth. How might the principles of teratology account for variability in outcomes, such
as these?
CHAPTER SUMMARY
3.1
Describe the three periods of prenatal development.
Conception occurs in the fallopian tube. During the germinal period, the zygote begins cell division
and travels down the fallopian tube toward the uterus. During the embryonic period, from weeks 2
to 8, the most rapid developments of the prenatal period take place. From 9 weeks until birth, the
fetus grows rapidly, and the organs become more complex and begin to function.
3.2
Explain how exposure to teratogens and other environmental factors can influence the prenatal
environment.
Teratogens include diseases, drugs, and other agents that influence the prenatal environment to
disrupt development. Generally, the effects of exposure to teratogens on prenatal development vary
depending on the stage of prenatal development and dose. There are individual differences in
effects, different teratogens can cause the same birth defect, a variety of birth defects can result
from the same teratogen, and some teratogens have subtle effects that result in developmental
delays that are not obvious at birth or not visible until many years later. Prescription and
nonprescription drugs, maternal illnesses, and smoking and alcohol use can harm the developing
fetus. Prenatal development can also be harmed by factors in the environment. Some states require
reporting of prenatal substance use, but enforcement and consequences often vary with maternal
demographic factors.
3.3
Compare the influence of maternal and paternal characteristics on prenatal development.
Fetal malnutrition is associated with poor growth before and after birth. Severe stress during
pregnancy also poses risks for low birthweight and premature birth, as well as a greater release of
stress hormones in newborns. Women who give birth over the age of 40 are at greater risk for
hypertension, preterm birth, miscarriage, and Down syndrome. Fathers’ age and behavior (such as
substance use) may also increase the risk of chromosomal abnormalities and developmental
disorders. Biological parents pass on epigenetic markers that can influence their offspring’s health
throughout life and may even be passed to their offspring’s children.
3.4
Identify barriers to prenatal care and intersectional influences on access to prenatal care.
Prenatal care is a set of services provided to improve pregnancy outcomes. Common reasons for
not obtaining prenatal care include lacking health insurance, difficulty in finding a doctor, lack of
transportation, lack of education about the importance of prenatal care, lack of social support, and
poor prior experiences in the health care system. There are significant racial, ethnic, and
socioeconomic disparities in prenatal care that are thought to be largely influenced by
socioeconomic factors, as the ethnic groups least likely to seek early prenatal care are also the most
economically disadvantaged members of society and are most likely to live in communities with
fewer health resources. Although prenatal care predicts better birth outcomes, cultural factors, such
as the Latina paradox, may protect some women and infants from the negative consequences of
inadequate prenatal care.
3.5
Summarize birth options and the process of childbirth.
Childbirth progresses through three stages. The first stage of labor begins when the mother
experiences regular uterine contractions that cause the cervix to dilate. During the second stage, the
fetus passes through the birth canal. The placenta is passed during the third stage. Medication is
used in most births, often in combination with breathing and relaxation techniques characteristic of
natural births, those without medication. Many women choose a doula to provide education and
,
y
p
support throughout the birth process. About one-third of U.S. births are by cesarean section, a birth
option chosen because of concerns for the health or safety of the mother or fetus. Societies vary in
their customs and perceptions of childbirth, including the privacy afforded to giving birth, where it
occurs, and how newborns are integrated into the community.
3.6
Examine risks for low birthweight, characteristics of low-birthweight infants, and ways of
supporting positive outcomes of low-birthweight infants.
Low-birthweight (LBW) infants, whether preterm or small for date, weigh less than 2,500 grams (5.5
pounds) at birth. The prevalence of low birthweight varies with ethnicity, socioeconomic status,
neighborhood, and access to resources such as prenatal care. Low-birthweight infants have
difficulty adapting to their environment. LBW infants are at higher risk for poor growth; health,
cognitive, and neurological problems; and difficult relationships with parents, including poor
attachment. When parents have knowledge about child development and how to foster healthy
development, are involved with their children, and create a stimulating home environment, lowbirthweight infants tend to have good long-term outcomes. Interventions help parents learn coping
strategies for interacting with their infants and managing stress.
3.7
Discuss the neonate’s physical capacities.
Newborns are routinely screened with the Apgar scale to assess their immediate health. The
Brazelton Neonatal Behavioral Assessment Scale (NBAS) is a neurobehavioral assessment commonly
administered in the first few days after birth to assess the newborn’s neurological competence.
Developmental researchers now know that the newborn is more perceptually competent than ever
imagined. The most well-developed sense is audition, evident before birth. Newborns display
regular cycles of eating, elimination, and states of arousal or degrees of wakefulness, spending
about 50% of their sleep time in REM, thought to permit the brain to stimulate itself.
Key Terms
Age of viability
Amnion
Anencephaly
Apgar scale
Blastocyst
Brazelton Neonatal Behavioral Assessment Scale (NBAS)
Breech position
Cesarean section
Developmental delays
Doula
Embryo
Embryonic period
Epidural
Extremely low birthweight
Fetal alcohol spectrum disorders
Fetal alcohol syndrome (FAS)
Fetal period
Fetoscopy
Fetus
Germinal period
Implantation
Kangaroo care
Labor
Lanugo
Low birthweight (LBW)
Midwife
Natural childbirth
Neonate
Neural tube
Placenta
Prenatal care
Preterm
REM sleep
Sleeper effects
Small for date
Spina bifida
States of arousal
Teratogen
Vernix caseosa
Very low birthweight
Zygote
Lifespan Development at Work Part 1: Foundations of Lifespan Human
Development
One of the tenets of lifespan development is that it is a multidisciplinary field, integrating findings from
many settings. In this feature that appears at the end of each major part of this book, we explore some
of the career choices for students interested in lifespan development.
Students with interests in human development select many different college majors, such as human
development and family studies, psychology, social work, education, nursing, and more. What these
diverse fields hold in common, besides a grounding in human development, is training in transferrable
skills that are valuable in a variety of employment settings.
Transferrable Skills
transferrable skill
transfer
Just as it sounds, a
is one that can
or be applied in multiple settings.
Employers value transferrable skills. Consider the top five attributes that employers seek in potential
employees (Table 3.3).
Table 3.3 Top 5 Key Attributes Employers Prefer in Applicants
Desired Attribute
Problem-solving skills
Ability to work in a team
Strong work ethic
Analytical/quantitative skills
Communication skills (written)
Percentage of Employers Endorsing
91%
86%
80%
79%
78%
Source: NACE (2020).
It might be quickly apparent that none of these attributes refer directly to any specific college major.
Instead, these are skills that students of all disciplines who study human development have the
opportunity to hone. Let’s take a closer look at some of these transferrable skills.
problem-solving
The skill employers view as more valuable is, perhaps not surprising,
. Individuals who
are successful at problem-solving can gather and synthesize information from a variety of sources. They
learn to weigh multiple sources of information, determine the degree of support for each position, and
generate solutions based on the information at hand. Effective problem-solving relies on
.
Exposure to diverse perspectives and ideas about human development trains students to think flexibly
and to accept some ambiguity because solutions to complex problems are often not clear-cut.
analytical skills
teamwork skills
Students in human development fields learn to work with others, or
, in coursework and
placements. For example, nursing, psychology, and human development and family studies students may
work together as lab members. Education students may collaborate on group projects, such as
designing curricula, and social work students may get hands-on experience working with others in field
placements. These valuable experiences foster the ability to effectively work with teams, a skill coveted
by employers of all fields.
Students in human development and family studies, psychology, social work, education, and nursing
take coursework relevant to their discipline, but success in each of these fields requires a
and good
. Succeeding in challenging courses like anatomy and physiology,
research methods, and statistics requires dedication and consistent work. Oral and written
communication skills are developed in coursework but also in field and practicum experiences, when
students learn to communicate with children, adolescents, adults, and supervisors.
ethic
strong work
communication skills
Lifespan Development Fields
As we consider career opportunities in lifespan development, we break them into several areas:
education; health care and nursing; counseling, psychology, and social work; and research and advocacy.
Education
Perhaps the most obvious career for students interested in human development is educator, or teacher.
Educators who work with young children include
and
.
Educators who work with older children and adolescents include
and
. Some educators specialize in working with children with specific developmental needs
(
). Other teachers specialize in teaching English as a second language (
) and work with children, adolescents, and adults. Becoming a teacher requires a bachelor’s
degree and certification.
early childhood educators preschool teachers
elementary school teachers high
ESL
school teachers
special education teachers
teachers
Career and technical education teachers provide vocational training to adolescents and adults in
subjects such as auto repair, cosmetology, and culinary arts. Adult literacy teachers instruct adults in
literacy skills such as reading and writing. GED teachers or instructors help students earn their GED
certificate, a high school equivalency diploma.
The education field also includes careers in administration, overseeing educational programs and
educators.
work with early childhood educators to design
educational plans for young children, oversee staff, prepare budgets, and are responsible for all aspects
of the program.
,
, and
oversee all school operations, including the work of teachers and other personnel, curricula, daily school
activities, and they promote a safe and productive learning environment.
Preschool and childcare center directors
Elementary school principals middle school principals
high school principals
college professor
Perhaps the most visible career at the college level is
. Becoming a professor requires
education beyond the bachelor’s degree, sometimes a master’s degree but more typically a doctoral
degree. However, there are many opportunities to work on a college campus with a bachelor’s degree.
But there are many other opportunities to work on college campuses. For example, every college and
university sponsors student activities, such as clubs, student government, and fraternities and sororities.
S
, or
, oversee the development and organization
of the college or university's extracurricular programs, including approving funding for student activities
and overseeing students and staff who organize and supervise student activities.
oversee the residence halls, ensuring that they are safe, supportive environments for students living on
campus.
tudent activities directors directors of student services
Resident directors
Health Care and Nursing
An understanding of human development is helpful to all who work in health care settings. There are
many kinds of nurses, and nurses of any specialty can benefit from understanding development.
Examples of nurses who specialize in human development include
, who provide care for
elderly patients.
work with infants, children, and adolescents.
provide
care to infants who are born preterm, low birthweight, or suffer health problems, from birth until they
are discharged from the hospital. A
provides gynecological care, especially concerning
pregnancy, labor, and delivery.
Pediatric nurses
nurse midwife
geriatric nurses
Neonatal nurses
All physicians must learn about human development as part of their medical education, but only some
specialize in working with people of particular ages.
are physicians who
specialize in female reproductive health, pregnancy, and childbirth.
treat infants, children,
and adolescents, and
treat older adults.
are medical doctors who treat patients,
geriatricians
Obstetrician-gynecologists
Pediatricians
Psychiatrists
conduct therapy, and prescribe medication. To specialize, physicians must complete additional training,
often a fellowship after earning their medical degree and obtaining licensure.
Allied health is a field of health care whose functions include assisting, facilitating, or complementing the
work of nurses, physicians, and other health care specialists.
assess clients and
provide recreational activities to individuals with physical or emotional disabilities in a variety of medical
and community settings.
design and provide treatments and interventions for
individuals suffering pain, loss of mobility, or other physical disabilities.
aid
patients with physical, developmental, or psychological impairments, helping patients develop, recover,
and maintain skills needed for independent daily living and working. Physical therapists and
occupational therapists must earn graduate degrees, but
and
may be hired with specialized associate degrees and certification.
Physical therapists
occupational therapists
Recreational therapists
Occupational therapists
assistant physical therapists
assistant
peech-language pathologists
assistant speech-language pathologists
Child life specialists
Other allied health care specialists include s
, who assess, diagnose, and
treat speech, language, and social communication disorders in children, adolescents, and adults. A
speech-language pathologist must earn a graduate degree and
may be hired with associate or bachelor’s degrees with specialized coursework and certification,
depending on the U.S. state.
typically work in hospital settings, helping children and
families adjust to a child’s hospitalization by educating and supporting families in the physically and
emotionally demanding process of caring for hospitalized or disabled children. An entry-level position as
a child life specialist requires a bachelor’s degree and certification.
Knowledge about health and development is also needed to become a health educator.
Health educators design and implement educational programs (classes, promotional pamphlets,
community activities) to educate individuals and communities about healthy lifestyles and wellness.
Social Work, Psychology, and Counseling
Children and adolescents have different needs and abilities to communicate than adults and older
adults. Professionals who work closely with individuals must understand how they change over their
lives.
Social workers help people improve their lives by identifying needed resources (such as housing or food
stamps) and providing guidance. Clinical social workers also conduct therapy and implement counseling
treatments with individuals and families. Entry-level social workers require a bachelor’s degree whereas
clinical social workers must earn a graduate degree and seek licensure.
Mental health
School counselors
There are many different types of counselors, each generally requiring a master’s degree.
help people manage and overcome mental and emotional disorders.
help
elementary, middle, and high school students develop skills to enhance personal, social, and academic
growth.
focus on the family system and treat individuals, couples, and
families to help people overcome problems with family and relationships.
help
people who suffer from addictions, helping them to recover and modify behaviors through individual
and group therapy sessions.
counselors
Marriage and family therapists
Substance use counselors
Applied behavior analysts apply scientific principles of learning to modify people’s behavior to improve
social, communication, academic, and adaptive skills in children, adolescents, and adults. They teach
parents, teachers, and support professionals how to implement behavioral procedures, skills, and
interventions. A position as an applied behavior analyst requires a graduate degree.
support the work of applied behavior analysts. They assist in gathering data or information
about clients, monitoring client progress and maintaining records, and administering assessments and
treatment under the supervision of the applied behavior analyst.
Assistant behavior
analysts
Clinical psychologists
counseling
Psychologists are doctoral-level mental health professionals.
and
conduct therapy with children, adolescents, adults, and families. Clinical psychologists
specialize in treating mental disorders, and counseling psychologists emphasize helping people adjust to
life changes.
work within school settings, assessing individuals’ learning and mental
health needs; collaborating with parents, teachers, and school administrators; designing interventions to
improve students’ well-being; and counseling students.
may,
depending on their training, assess and treat children, adolescents, and adults, and design and evaluate
intervention programs to address problems and enhance the development of people of all ages.
psychologists
School psychologists
Applied developmental psychologists
Research and Advocacy
Developmental scientists design and conduct research on social problems and apply their findings to
advocate on behalf of individuals and families. They are employed at social service agencies, nonprofits,
and think tanks conducting research to gather information about social problems and policies; assess
and improve programs for children, youth, and families; and write reports and other documents to
inform policymakers and the public. Some work as program directors and administrators for these
programs. Others assess programs.
foundation directors
Some developmental scientists head nonprofit organizations as
. They develop
goals and strategies in line with the foundation’s mission statement and oversee all activities within an
organization, including program delivery, program evaluation, finance, and staffing. Other
developmental scientists work as
, submitting proposals to fund programs. Organizations
that award grants to others have
who oversee the funding process by analyzing grant
proposals, communicating with applicants, and determining which proposals are suitable for funding.
grant writers
grant directors
Developmental scientists conduct research in a variety of settings. Some work at universities and apply
their research findings to help people. For example, a researcher might conduct experiments in a lab to
identify influences on electronic cigarette use in children, adolescents, and adults then apply the
findings to develop prevention programs tailored to each age group. Developmental scientists who
work for the government might evaluate government-supported social-media-based health initiatives
(such as those targeting distracted driving) or educational initiatives, such as the effects of providing free
kindergarten to children.
Developmental scientists working in business and industry help companies design materials, such as
toys, products, and media, that fit people’s needs and abilities. They might determine the developmental
appropriateness of toys and provide insight into children’s abilities or examine children’s and parents’
reactions to particular toys, advertising, and promotional techniques. Others might provide
developmental and educational advice to creators of children’s media, such as by interpreting research
on children’s attention spans to inform creative guidelines for television programs such as
.
Street
Sesame
Developmental scientists also assist companies in developing and marketing products that are
appropriate for older adults. A consultant might suggest modifying the design of product packaging by
using contrasting colors and larger print that is easier for older adults to read. A developmental scientist
might research ways of modifying a car’s dashboard to include displays and knobs that can be easily
viewed and used by older adult drivers.
Careers in Genetics and Prenatal Development
Genetic Counselor
As we have seen in Chapter 2, many chromosomal abnormalities are passed through genetic inheritance.
Genetic counselors help assess the risk of an individual or couple passing a genetic disorder to their
offspring.
Genetic counselors interview individuals and couples to gather information about their family history,
educate them about the risks for particular genetic conditions in their offspring, and inform them about
the different genetic tests available to them. Genetic counselors also help individuals and couples
understand the results of DNA and other laboratory tests and the potential implications for offspring.
Genetic counselors typically work in a hospital or clinic setting but may work in private practice
Genetic counselors typically have a master’s degree in genetics or genetic counseling from a program
certified by the Accreditation Council for Genetic Counseling and pass a national certification exam.
Some genetics counselors specialize in a particular area, such as cancer, psychiatric, or genomic health.
The median annual salary for genetic counselors was $85,700 in May 2020 (U.S. Bureau of Labor
Statistics, 2021).
Midwife
A midwife is a health care professional who supports and cares for women throughout their pregnancy,
including delivering babies during childbirth. They collaborate with other health care professionals,
including obstetricians, nurses, and hospital staff.
There are two main paths to becoming a midwife, with different levels of expertise, certification, and
autonomy. Some midwives are referred to as direct-entry midwives because, after earning a bachelor’s
degree, they are trained and certified (through the North American Registry of Midwives) but do not
have a nursing degree. The legal status and requirements to become a direct-entry midwife vary by
state, but many states do not permit midwives without nursing degrees. Carefully research state
requirements before choosing this option.
The second path to becoming a midwife is to earn a nursing degree and complete a master’s program in
nurse-midwifery education. A certified nurse midwife can practice independently in every state. Most
people are familiar with the labor and delivery activities of nurse midwives. Nurse midwives may focus
on all parts of pregnancy and birth, from preconception to postpartum. The nurse-midwife practice
includes a variety of services in reproductive health visits, preventative care, and post-menopausal care.
They can prescribe medication, and admit or discharge patients if needed.
Nurse midwives can work in a variety of settings, including hospitals, birth centers, health centers, and in
private practice. The median annual wage for nurse midwives was about $111,000 in 2020 (U.S. Bureau
of Labor Statistics, 2021).
Doula
Doulas provide physical, emotional, and educational support to expectant mothers prior to birth, during
labor, and immediately after birth through the first few weeks. Doulas provide education about labor,
medication, and comfort during the birth process. Doulas also support the partner and family to aid their
participation in the birth process.
The educational requirements to become a doula include a high school degree and completion of a
doula education program. Some employers prefer college credits or a degree. Doulas work in hospitals,
private practices, birth centers, or community organizations. Doulas’ earnings vary with work setting,
experience, and location. A common national hourly rate is about $45 per hour, as high as $70 in large
urban cities and as low as $25 per hour in small towns.
Descriptions of Images and Figures
Back to Figure
On the left side is a representative image of a human female with the location of the female
reproductive organs marked. On the right side is the uterus with fallopian tubes and ovaries attached.
Uterus, vagina, cervix, ovaries, fallopian tube, follicles, corpus luteum, and uterine wall are marked and
labeled on the right side figure.
Back to Figure
Within the ovary developing follicles and corpus luteum are marked and labelled. Ovulation releases
ovum and it enters the fallopian tube. Fertilization takes place there. Within the fallopian tube, cell
division begins and zygote enters the morula stage. The blastocyst with an inner cell mass follows this.
Implantation takes place within the uterus.
Back to Figure
Weeks 1 and 2 of prenatal development comprise the period of dividing zygote, implantation, and
bilaminar embryo. Morula and blastocyst, aspects of cell division, are illustrated in the Week 1 column.
Embryonic disc and amnion, aspects of cell division, are illustrated in the Week 2 column. The zyote or
embryo is not susceptible to teratogenesis during this period. Death of embryo and spontaneous
abortion are common during this period. The Main Embryonic Period runs from Week 3 through Week 8,
followed by the Fetal Period from Week 9 through Week 38. A row of images of the embryo and fetus by
week appears across the top in chronological order. The rows below this indicate common sites of action
of teratogens during the Embryonic and Fetal periods. The labels for less sensitive periods (earlier in
development) are shaded in blue, and the ones for highly sensitive periods (later in development) are
shaded in green. Weeks 3 through 6, in the Embryonic Period, are less sensitive for neural tube defects
or NTDs. Weeks 7 through 16, spanning the Embryonic and Fetal periods, are less sensitive for mental
retardation. Fetal Weeks 32 through 38 are highly sensitive for CNS. Around the middle of Week 3
through the middle of Week 6, during the Embryonic Period, is less sensitive for truncus artoriosus, atrial
septal defect, and ventricular septal defect. From around the middle of Week 6 through Week 8, in the
Embryonic Period, is highly sensitive for heart. Embryonic Weeks 4 and 5 are less sensitive for amelia and
meromelia, while late in Week 5 through Week 8 is highly sensitive for upper limb. From early in
Embryonic Week 4 through Week 5 is less sensitive for amelia and meromelia, while Weeks 6 through 8
are highly sensitive for lower limb. Embryonic Weeks 5 and 6 are less sensitive for cleft lip. Embryonic
Weeks 7 and 8 are highly sensitive for upper lip. About the middle of Week 4 through the middle of
Week 9, spanning the Embryonic and Fetal Periods, is less sensitive for low-set malformed ears and
deafness. From the middle of Fetal Week 9 through the beginning of Fetal Week 32 is highly sensitive for
ears. From the middle of Week 4 through approximately the middle of Week 8 in the Embryonic period
is less sensitive for microphthalmia, cataracts, and glaucoma. From late in Week 8 through Week 38,
spanning the end of the Embryonic and all of the Fetal Period, is highly sensitive for eyes. From late in
Embryonic Week 6 through Week 8 is less sensitive for enamel hypoplasia and staining. Fetal Weeks 9
through 38 are highly sensitive for teeth. From late in Embryonic Week 6 through early in Fetal Week 9 is
less sensitive for cleft palate. Fetal Week 9 is highly sensitive for palate. From around the middle of
Embryonic Week 7 through Fetal Week 9 is less sensitive for masculinization of female genitalia. From
late in Fetal Week 9 through Week 38 is highly sensitive for external genitalia. At the bottom of the
figure, the Main Embryonic Period is labeled “major congenital anomalies,” and the Fetal Period is
labeled “functional defects and minor anomalies.”
Back to Figure
The horizontal axis represents years ranging from 1990 to 2017. The vertical axes on the left and right
sides represents rates per 1, 000 women ranging from 1 to 200. The data from the graph are shown in
the table below. Values are approximate.
Year
Rate per 1, 000 women
15-19 yrs 20-24 yrs 25-29 yrs
1990 60
106
107
1995 51
100
100
2000 49
100
100
2005 40
99
104
2010 37
82
104
2015 20
78
102
2017 19
74
99
Back to Figure
30-34 yrs
80
81
90
97
97
100
100
35-39 yrs
31
33
39
41
40
50
51
40-44 yrs
5.5
7
8
8.9
9.5
12
13
The horizontal axis represents mother’s age in years, which include <20, 20-24, 25-29, 30-34, 3539 and 40+. The vertical axis represents prevalence (per 10,000 live births) ranging from 0 to 120 in
increments of 20. The data from the graph is shown in the table below. Values are approximate.
Mother’s age (years)
<20
20-24
25-29
30-34
35-39
40+
Back to Figure
Prevalence (per 10,000 live births)
10
10
12
15
40
120
The horizontal axis shows the percent of recent mothers ranging from 10 to 50, in increments of 10 and
the vertical axis shows the reasons for delayed prenatal care among women.
The data from the graph are shown in the table below.
Percentage of Recent Mothers Reasons for delayed prenatal care among women
7.9
Needed child care for other children
9.8
Could not take time off work or school
13.9
13.9
19.7
24.1
36.4
37.1
37.8
38.7
Back to Figure
Didn’t want anyone to know about pregnancy
Lacked transportation to clinic or doctor’s office
Mother was too busy
Doctor or health plan did not start as early as desired
Didn’t have a Medicaid card
Didn’t know she was pregnant
Couldn’t get appointment when desired
Lacked money or insurance for visits
The horizontal axis depicts the percent of mothers ranging from 0 to 100 in increments of 20 and the
vertical axis shows the maternal education.
The data from the graph are shown in the table below.
Maternal Education
Percent of mothers
First Trimester Second Trimester
Bachelor’s Degreeor Higher
86.1
11.2
Some College orAssociate’s Degree 76.1
19.0
High SchoolDiploma or GED
68.6
24.2
Less than HighSchool Diploma
58.5
30.1
Total
74.1
19.9
Back to Figure
Third Trimesteror No Care
2.7
4.9
7.2
11.4
6.0
The horizontal axis represents ethnicities and the vertical axis represents the percent care ranging from 0
to 100, in increments of 20. The graph plots the data for ethnicities in the first trimester and late or no
prenatal care.
The data from the graph are shown in the table below.
Ethnicities
Percent care
First Trimester
All races andorigins
77.5
White
82.5
Black
67.1
American Indianor Alaska Native
62.5
Asian
81.8
Native Hawaiianor Other PacificIslander 50.9
Hispanic
72.7
Back to Figure
Late or no prenatal care
6.2
4.5
9.9
13.2
4.9
20.4
7.7
The top diagram has urinary bladder, vagina, raptured amniotic sac and rectum labeled and marked. The
fetus is in an upside down position and its head is near the cervix. The middle diagram has placenta
marked and labeled. The head of the fetus is almost outside the outer opening of vagina. The bottom
most diagram has uterus, placenta and umbilical cord marked and labeled. One end of the umbilical
cord is attached to the placenta and its outer end is outside the vagina.
Back to Figure
Horizontally ’All races and White Asian Hispanic origins’, ’White’, ’Black’, ’American Indian or Alaska
Native’, ’Asian’, ’Native Hawaiian or Other Pacific Islander’ and ’Hispanic’ are depicted and ‘Percentage’
starts from 0 to 25 with the interval of 5 along vertical axis. The bar graph depicts ‘Preterm’ as the
highest for all groups and ’Very low birthweight’ as stable and least to all groups. ’Low birthweight’ and
‘Preterm’ are almost same and maximum for black. ’Moderately low birthweight’ is almost same for all
groups.
PART II INFANCY AND
TODDLERHOOD
4 PHYSICAL DEVELOPMENT IN INFANCY AND
TODDLERHOOD
AJ_Watt/Getty
“You’re such a big girl!” the pediatric nurse exclaimed as she weighed baby Hyla. Hyla’s mother marveled
at how much her daughter had grown during the first 6 months of her life—she had more than doubled
her weight. Over 6 months, Hyla transformed from a newborn unable to raise her head into a baby who
can sit up on her own. Her mother told the nurse, “She seems to like spending time on all fours, pushing
and rocking. Maybe she’s getting ready to crawl.” The nurse smiled and said, “Start thinking about
babyproofing your home because Hyla will be crawling before you know it!” Over the next few months,
Hyla will crawl, pull herself up to stand, and eventually walk. Babies grow and change very quickly. In this
chapter, we explore the physical changes that occur in a child’s first 2 years of life. These first years are
collectively called the developmental stage of infancy and toddlerhood. The term
refers to
toddling, the unsteady gait of babies who are just learning to walk. During this stage, infants and
toddlers experience advances in growth, perceptual capacities, and motor skills that enable them to
interact with their world and learn in new ways.
toddler
BODY GROWTH DURING INFANCY AND TODDLERHOOD
LEARNING OBJECTIVE
4.1 Discuss patterns of growth and influences on growth during infancy and toddlerhood.
Perhaps the most obvious change that infants undergo during the first year of life is very rapid growth.
Growth Trends
It is easy to observe that infants grow substantially larger and heavier over time—but there are many
individual differences in growth. How can parents and caregivers tell if a child’s growth is normal? By
compiling information about the height and weight of large samples of children from diverse
populations, researchers have determined that growth follows distinct patterns. Growth norms are
p p
g
p
expectations for typical gains and variations in height and weight for children based on their
chronological age and ethnic background.
In the first few days after birth, newborns shed excess fluid and typically lose 5% to 10% of their body
weight. After this initial loss, infants gain weight quickly. Infants typically double their birth weight at
about 4 months of age, triple it by 12 months, and quadruple it by 2.5 years (Kliegman & Geme, 2020).
The average 3-year-old weighs about 31 pounds. Gains in height of 10 to 12 inches can be expected
over the first year of life, making the average 1-year-old child about 30 inches tall. This increase is
caused by gains in bone and represents the greatest growth spurt of the lifespan (Ohta, 2019). Most
children grow about 5 inches during their second year of life and 3 to 4 inches during their third. To
parents, growth may appear slow and steady, but research has shown that it tends to occur in spurts in
which an infant or toddler can grow up to one quarter of an inch overnight (Lampl et al., 2001). Infant
growth is linked with sleep; increased bouts of sleep are associated with small bursts of growth (Lampl &
Johnson, 2011). At about 2 years of age, both girls and boys have reached one half of their adult height
(Kliegman & Geme, 2020).
Patterns of Growth
Over the course of infancy children get larger and heavier, but growth is uneven. Different parts of the
body grow at different rates. Growth during the prenatal period and infancy proceeds in two systematic
patterns. Cephalocaudal development refers to the principle that growth proceeds from the head
downward. The head and upper regions of the body develop before the lower regions. Recall the fetus’s
disproportionately large head. During prenatal development, the head grows before the other body
parts. Even at birth, the newborn’s head is about one-fourth the total body length (Figure 4.1). As the
lower parts of the body develop, the head becomes more proportionate to the body. By 3 years of age,
the child is less top-heavy.
Figure 4.1 Body Proportions Throughout Life
Source: Adapted from Huelke (1998).
Proximodistal development refers to the principle that growth and development proceed from the
center of the body outward (Figure 4.2). During prenatal development, the internal organs develop
before the arms and legs. After birth, the trunk grows ahead of the arms and legs, and the arms and legs
tend to grow before the hands and feet.
Figure 4.2 Cephalocaudal and Proximodistal Development
Growth is largely maturational, but it can be influenced by health and environmental factors, such as
socioeconomic status (Von Holle et al., 2020). Today’s children grow taller and faster than prior
generations, and the average adult is taller today than a century ago. Increases in children’s growth over
the past century are influenced by contextual changes such as improved sanitation, nutrition, and access
to medical care (Mummert et al., 2018). The largest gains in infant growth have occurred in North
America and Europe, followed by South Asia (NCD Risk Factor Collaboration, 2016). Although children of
sub-Saharan Africa showed growth gains into the mid-1990s, mass poverty and starvation, poor
infrastructure to provide clean water and sanitation, and exposure to the emotional and physical stresses
of war and terror have affected growth (Simmons, 2015). Contextual factors, such as nutrition, influence
growth.
Nutrition and Growth
The first two years of life are a critical window for promoting optimal health and development
throughout childhood through adequate caloric intake and good nutrition. An important way that
mothers can aid their infants’ nutrition is through breastfeeding. The USDA Dietary Guidelines Advisory
Committee (2020) and American Academy of Pediatrics (American Academy of Pediatrics, 2012)
recommend that infants be breastfed exclusively until about 6 months and, preferably, 1 year.
Breastfeeding
Over the past several decades, breastfeeding has increased in popularity in the United States. In 1990,
about one half of mothers breastfed their babies, rising to 83% breastfed in 2015 (Centers for Disease
Control and Prevention, 2019a; Centers for Disease Control and Prevention, 2017). Nearly two-thirds of
women continue to breastfeed after 6 months and over one-third at 12 months. In the United States,
breastfeeding rates are linked with the length of maternity leave (Ogbuanu et al., 2011). The U.S.
government mandates a 12-week unpaid maternity leave for all women, but many women are unable to
afford unpaid maternity leave. Countries where working women are allowed paid maternity leave for
part or all of their infant’s first year of life, such as Denmark, Norway, Sweden, and Australia, show very
high breastfeeding rates of 94% and more (Hauck et al., 2011; Imdad et al., 2011; Roelants et al., 2010).
There is geographic variation in breastfeeding rates in the United States, with a greater prevalence of
breastfeeding among women in the Northeastern and Western states than in the South and Midwest
(Anstey et al., 2017; Grubesic & Durbin, 2019).
Breastfeeding practices vary by maternal age, education, and socioeconomic status (Dinour et al., 2020;
Hauck et al., 2011). In the United States and the United Kingdom, the lowest rates of breastfeeding are
among low-income mothers, mothers who are young, and mothers with low levels of education. In
contrast, women in developing countries who have low educational levels and are in the poorest social
classes are
likely to breastfeed their children. In these countries, educated women of higher
income brackets in these countries tend to shun breastfeeding, viewing it as an option primarily for poor
women (Victora et al., 2016).
more
There are ethnic and racial differences in breastfeeding among U.S. mothers. Hispanic mothers in the
United States breastfeed at higher rates than white mothers, who are more likely to breastfeed than
Black mothers (Beauregard et al., 2019; Centers for Disease Control and Prevention, 2013; McKinney et
al., 2016; Smith-Gagen et al., 2014). Racial differences are the result of contextual influences. Black
mothers disproportionately experience barriers to breastfeeding, such as lack of knowledge about
breastfeeding, lack of social support for breastfeeding, and breastfeeding restrictions at work (Jones et
al., 2015). Maternity care facilities in neighborhoods with Black mothers are more likely to provide
insufficient education for breastfeeding and are less likely to provide support such as helping women
initiate breastfeeding within the first hour of birth, which increases rates of breastfeeding initiation,
duration, and exclusivity (Lind et al., 2014; Pérez-Escamilla et al., 2016). Although Hispanic mothers often
experience similar contextual disadvantages as Black mothers, the factors that contribute to healthy birth
outcomes (known as the Latina paradox; see Chapter 3) may also support breastfeeding after birth (Fryer
et al., 2018).
In addition, the employment settings of low-income mothers may offer few resources to support
breastfeeding, such as private places or sufficient periods of time for women to use breast pumps
(Griffiths et al., 2007; Racine et al., 2009). Although the U.S. Affordable Care Act of 2010 includes a
provision known as
to support working, breastfeeding mothers, only
about one-half of U.S. states have legislation related to breastfeeding in the workplace (Hilliard &
Schneidermann, 2020).
Break Time for Nursing Mothers
Breastfeeding offers benefits for mothers and infants. Mothers who breastfeed have lower rates of
diabetes, cardiovascular disease, depression, arthritis, and cancer (Louis-Jacques & Stuebe, 2018; Sattari
et al., 2019). A mother’s milk is tailored to her infant and has the right amount of fat, sugar, water, and
protein needed for the baby’s growth and development. Most babies find it easier to digest breast milk
than formula. In addition, breast milk contains immunizing agents that protect the infant against
infections, and breastfed infants tend to experience lower rates of allergies and gastrointestinal
symptoms as well as have fewer visits to physicians (Cabinian et al., 2016; Turfkruyer & Verhasselt, 2015).
Breastfeeding for more than 6 months is associated with reduced risk of childhood obesity and cancer,
especially lymphomas (Amitay et al., 2016; Qiao et al., 2020; Victora et al., 2016). Exclusively
breastfeeding during the first 4 to 6 weeks of life may be associated with longer telomeres (protective
caps on chromosomes that predict lifespan longevity) at ages 4 and 5 (Wojcicki et al., 2016).
Research on the effects of breastfeeding on cognitive development yields mixed findings. In some
studies, infants breastfed for more than 6 months perform better on tests of cognitive ability compared
with their formula-fed counterparts (Kramer et al., 2008; Sloan et al., 2010). Others suggest that the
differences in test scores are influenced by the characteristics of mothers who breastfeed, such as higher
levels of education and socioeconomic status (Schulze & Carlisle, 2010; Tanaka et al., 2009). Yet studies
that control for maternal factors still support a cognitive advantage to breastfed infants (Sloan et al.,
2010). The cognitive advantages may persist throughout childhood into adolescence. The duration of
breastfeeding, specifically longer than 6 months, is associated with higher scores in cognitive and
language ability from early childhood through adolescence (Isaacs et al., 2010; Lenehan et al., 2020; Min
Kim & Choi, 2020; Whitehouse et al., 2011). Although breastfeeding appears to be associated with
positive cognitive outcomes, it is important to recognize that differences in cognitive development
between breastfed and formula-fed infants are small (Jenkins & Foster, 2014; Min Kim & Choi, 2020).
Breastfeeding is associated with many health benefits for infants and
mothers, and provides opportunities for infant–mother bonding.
iStock/SelectStock
Pediatricians recommend breastfeeding, but it is not essential for a healthy infant. Many mothers do not
breastfeed, whether by choice or circumstance. Infant formula is a safe and healthy alternative to breast
milk because formula production is monitored by the U.S. Food and Drug Administration.
Complementary Food
At about 6 months, and as early as 4 months, breast or formula feeding may be supplemented with
complementary food, commonly referred to as “solid food.” The first food consumed is usually vitaminand iron-fortified baby cereal mixed with breast milk or formula. As babies get older, the amount of milk
is reduced. Now, infants’ diets begin to include other pureed foods, such as vegetables and fruits, and
later meats. Infants do not necessarily like these new flavors and textures—many foods must be
introduced over a dozen times before an infant will accept them.
The USDA (Dietary Guidelines Advisory Committee, 2020) recommends that infants younger than age 2
avoid consuming beverages with added sugar, such as sweetened fruit juices, sports drinks, and soda.
The calories consumed from such beverages are filling and leave less “room” for energy from nutritious
food, leading to potential nutrient gaps. Sugary beverages may also increase the risk of the child being
overweight and may be associated with a greater intake of sugary beverages throughout life.
Many infants are not served nutritious foods. One study of 6- to 24-month-olds found that many were
served fattening “junk” foods such as french fries, pizza, candy, and soda, and 20% of the infants have
never consumed vegetables (Miles & Siega-Riz, 2017). Most infants are introduced to sweets early, and
by 24 months nearly two-thirds consume cookies or candy in a given day (Deming et al., 2017). Rapid,
excessive weight gain in infancy is associated with childhood obesity (Wang et al., 2016). Pediatricians
consider infants’ growth in light of norms to determine whether intervention is needed.
Thinking in Context: Applied Developmental Science
Eight months pregnant, Monique is considering breastfeeding her newborn.
g
p g
q
g
1. What are some of the benefits of breastfeeding?
g
2. What are some of the challenges that can interfere with breastfeeding?
3. To what degree are women equally likely to experience these difficulties? What individual and
contextual factors contribute to whether a woman breastfeeds?
4. If she chooses to breastfeed, what steps can Monique take to improve the odds of success?
THREATS TO INFANT HEALTH
LEARNING OBJECTIVE
4.2 Examine threats to infant and toddler health.
In general, infants are healthier than ever before. The risk of infant mortality, or death, is highest during
the first month of life and declines rapidly with age (Ely & Driscoll, 2019). Threats to infants’ health
include malnutrition and poor growth, failure to vaccinate, and sudden infant death syndrome.
Infant Mortality
The leading causes of infant death include birth defects, low birthweight, sudden infant death syndrome,
respiratory distress, and unintentional injuries, accounting for over two-thirds of deaths(Singh & Yu,
2019). Over the past century in the United States, infant mortality, or death, has declined for infants of all
races and ethnicities. Despite declines, there are large racial disparities in infant mortality rates (Figure
4.3). In 2017, infants of non-Hispanic Black women showed the highest rates of mortality, over twice that
of infants of non-Hispanic white women and Hispanic women and nearly three times that of nonHispanic Asian women (Ely & Driscoll, 2019). Infants of Native American/Alaskan Native and Native
Hawaiian/Pacific Islander women also showed high rates of mortality.
Description
Figure 4.3 Infant, Neonatal, and Postneonatal Mortality Rates, by Race and
Hispanic Origin: United States, 2017
Source: Ely & Driscoll (2019).
There are large educational disparities in infant mortality that have increased in recent decades. Infants
whose mothers have less than a high school degree show more than double the rate of mortality than
those with mothers with a college degree (Singh & Yu, 2019). Likewise, the large income differences
linked with education are associated with a higher risk of infant mortality. Poverty rates are at least two
times higher among Black, Hispanic, Native Hawaiian/Pacific Islander, and Native American/Alaskan
Native than non-Hispanic whites (Semega et al., 2020). However, infant mortality rates are highest in
Black infants across all income levels (Kothari et al., 2017). Infant mortality is also higher in rural counties
than urban counties in the United States (Ely & Hoyert, 2018).
Similar to our discussion of prenatal care, structural factors influence the racial and ethnic differences
that characterize infant mortality. Poverty—and its interweaving with stress and trauma, poor
environmental quality and exposure to pollution, and exposure to discrimination—poses risks to
maternal and infant health. Risk factors for infant mortality also include little to no prenatal care, lower
rates of health insurance, and poor access to health care. In addition to financial constraints, racism,
stereotypes, and bias may prevent women of color from regularly accessing health care.
Malnutrition
Many infants experience malnutrition, with devastating effects on physical growth. One in four children
in the world suffer from growth stunting, a reduced growth rate. Children in developing countries are at
especially high risk of chronic malnutrition and growth stunting. Growth stunting affects 43% of children
in East African countries, 34% in West Africa, and 35% in South-Central Asia (de Onis & Branca, 2016).
Infants who consume a diet that is chronically insufficient in calories, nutrients, and protein can develop
marasmus, a wasting disease in which the body’s fat and muscle are depleted (Kliegman & Geme, 2020).
Growth stops, the body wastes away, the skin becomes wrinkly and aged looking, the abdomen shrinks,
and the body takes on a hollow appearance. Another disease related to malnutrition is kwashiorkor,
found in children who experience an insufficient intake of protein, which may occur when a child
prematurely abandons breastfeeding, such as after the birth of a younger sibling. It is characterized by
lethargy, wrinkled skin, and a fluid retention appearing as bloating and swelling of the stomach, face,
legs, and arms. Because the vital organs of the body take all of the available nutrients, the other parts of
the body deteriorate. Marasmus occurs most often in infants whereas kwashiorkor tends to occur in
older infants and young children (Morley, 2016).
This child suffers from an extreme nutritional deficiency, kwashiorkor. Early
treatment can reduce the deficits associated with kwashiorkor, but most
children will not reach their full potential for height and growth.
Dr. Lyle Conrad—Centers for Disease Control and Prevention, Atlanta, Georgia, USA Public Health Image
Library (PHIL); ID: 6901 http://phil.cdc.gov/
Malnutrition influences development in multiple ways. Malnourished children show cognitive deficits as
well as impairments in motivation, curiosity, language, and the ability to effectively interact with the
environment throughout childhood and adolescence and even into adulthood (Galler et al., 2012; Peter
et al., 2016). Malnourishment damages neurons, as shown in Figure 4.4, and the resulting neurological
and cognitive deficits from early malnutrition last. Among Ghanan children who survived a severe famine
in 1983, those who were youngest at the time of the famine (under age 2) scored lower on cognitive
measures throughout childhood and into adulthood than did those who were older (ages 6 to 8)
(Ampaabeng & Tan, 2013). Malnutrition during the first year of life is associated with depression years
later, when those children are 11 to 17 years old (Galler et al., 2010). Some of the damage caused by
malnutrition can be reversed. Motor and mental development can be enhanced if nutrition is reinstated
early. However, long-term difficulties in attention, learning, and intelligence often remain, even into
middle adulthood (Schoenmaker et al., 2015; Waber et al., 2014).
Figure 4.4 Effects of Malnourishment on Brain Development
Source: De Onis & Branca (2016).
Although malnutrition is common in developing countries, it is also found in some of the world’s
wealthiest countries. Because of socioeconomic factors, many children in the United States and other
developed countries are deprived of diets that support healthy growth (Ngandu et al., 2019). In 2017,
about 16% of U.S. households with children were categorized as
. That is, they lacked
consistent access to food to support a healthy lifestyle for all members of the family at some point
during the year (Coleman-Jensen et al., 2018). As shown in Figure 4.5, rates of food insecurity are higher
in Black and Hispanic households (22% and 18%, respectively) and those headed by single parents (20%
for homes headed by single men and 30% for those headed by single women). In the United States and
other developed nations, food insecurity is linked with stunted growth, poor school performance, and
health and behavior problems (Shankar et al., 2017; Zhu et al., 2017).
food insecure
Description
Figure 4.5 Food Insecurity in the United States, 2017
Source: Coleman-Jensen et al. (2018).
Growth Faltering
Although growth follows particular norms, children’s rate of growth varies with hereditary and contextual
factors. Some children show significantly slower growth than other children their age. Some infants
demonstrate growth faltering, also known as
, a condition in which their growth and
weight are substantially lower than other children their age. Specifically, growth faltering refers to weight
that falls below the fifth percentile for their age, meaning that the child weighs less than 95% of sameage children (Raab, 2017). Their caloric intake is insufficient to maintain growth (Larson-Nath & Biank,
2016). Growth faltering can be caused by the malnutrition associated with poverty.
failure to thrive
Children with growth faltering may be irritable and emotional, lack age-appropriate social responses
such as smiling and eye contact, and show delayed motor development. Untreated, growth faltering is
accompanied by delays in cognitive, verbal, and behavioral skills that make it difficult for the child to
achieve success in school, home, and peer environments (Homan, 2016).
Growth faltering may be influenced by medical conditions, such as kidney and liver disease, cystic
fibrosis, HIV, cancer, and irritable bowel disease (McAlpine et al., 2019). Sometimes socioemotional and
contextual factors contribute to growth faltering, such as an insecure attachment to caregivers, parents
with physical or mental health problems, emotional neglect and abuse, and, especially, living in poverty
and experiencing contextual stressors such as violence within the community (Feigelman & Keane, 2017).
Pediatricians typically treat growth faltering by providing the child with the nutrients necessary to grow
normally. They may also work with other health professionals such as psychologists and social workers to
address underlying medical and psychosocial contributors. Although nutritional interventions can
alleviate many of the effects of malnutrition on physical development, some children might show longterm cognitive and psychosocial deficits (Larson-Nath & Biank, 2016; McAlpine et al., 2019).
Failure to Vaccinate
Through the use of vaccines, measles, a highly contagious infection, was declared eliminated from the
United States in 2000. Over the past 60 years, childhood diseases such as mumps, rubella, and whooping
cough have declined dramatically because of widespread immunization of infants. A vaccine is a small
dose of inactive virus that is injected into the body to stimulate the production of antibodies to guard
against the disease. Vaccines control infectious diseases that once spread quickly and killed thousands of
people. The Centers for Disease Control and Prevention (CDC) recommends that infants be vaccinated
against most vaccine-preventable diseases by the time they are 2 years of age.
Currently, 10 vaccines are included in the standard recommendations for children at specific ages
between birth and 10 years. Immunization rates vary by vaccine, but overall vaccination coverage in the
United States tends to be high. In 2016, 91% of children 19 to 35 months of age were vaccinated for
measles, mumps, and rubella (MMR) (National Center for Health Statistics, 2018). The percentage of
children who have received no vaccines has increased over the past two decades, from .3% of 19- to 35month-old children in 2001 to 1.3% for children born in 2015 (Hill et al., 2018). Although only a small
minority of children are unvaccinated, highly contagious diseases, such as measles, can spread quickly
among them. In 2019, nearly 900 cases of measles were reported, largely confined to geographic areas
where vaccination is less common (Centers for Disease Control and Prevention, 2019b).
Some parents decline or delay vaccinating their children or follow alternative immunization schedules
because of medical, religious, philosophical, or socioeconomic reasons (Ventola, 2016). Vaccination is
compulsory for school-age children in the United States, but all states permit exemptions for medical
and religious reasons and sometimes philosophical objections (Bednarczyk et al., 2019; Wang et al.,
2014). It has been estimated that 1% to 3% of children are excused from immunization because of these
exemptions, but in some communities the exemption rate is as high as 20% (Ventola, 2016). Exemptions
may pose threats to public health because the risk of disease outbreaks in schools increases when even
a low percentage of children are excused from immunization (Goldstein et al., 2019).
Some parents choose not to vaccinate their children because of the common misconception that
vaccines are linked with autism (Salmon et al., 2015). Extensive research indicates that there is no
association between vaccination and autism (Modabbernia et al., 2017; Taylor et al., 2014). Instead,
children tend to receive vaccines at the age when some chronic illnesses and developmental disorders—
such as autism—tend to emerge, but this correlation is not indicative of a cause-and-effect relationship.
(Recall from Chapter 1 that correlational research documents phenomena that occur together but
cannot demonstrate causation.) Other parents report concerns about chemicals in vaccines and possible
unforeseen future effects of vaccination (Martin & Petrie, 2017). Yet longitudinal research has suggested
no negative long-term effects of vaccines administered in infancy (Henry et al., 2018; Su et al., 2017;
Wessel, 2017).
Some researchers argue that, paradoxically, one reason that parents may hesitate to vaccinate their
children is the widespread success of immunization (Temoka, 2013). Because of high vaccination rates
most vaccine-preventable diseases have declined to historically low levels in the United States, which
can mask the health dangers of once-common infections. With little to no experience with vaccinepreventable diseases, young parents may be unaware of the threat posed by them or the need to seek
protection.
A challenge to immunizing children is that the vaccination schedule is complicated, with specific
vaccines administered at specific times in development (Kurosky et al., 2017). Even when children receive
the full schedule of vaccinations, many do not receive them on the timetable recommended by the
National Vaccine Advisory Committee. Vaccine timeliness is important because the efficacy of early and
late vaccination is not always known and may vary by disease. When a child receives a vaccination may
be just as important as whether the child receives it in promoting disease resistance.
Vaccines protect children and communities from diseases that once spread
quickly and killed thousands of people.
iStock/spukkato
Children in families with incomes below the poverty level are less likely to receive the combined series
vaccination (Child Trends Databank, 2015). Many parents are unaware that children from low-income
families who do not have medical insurance can receive vaccinations through the federal Vaccines for
Children Program, which began in 1994. Interventions to increase vaccination rates tend to focus on
education and counseling and improving access to vaccines (Ventola, 2016). Health care workers can
inform parents about vaccination by describing the infections that they prevent, the research supporting
their use, and dispel myths. Offering combination vaccines that include several at once minimizes the
number of injections and visits. Providing opportunities to administer vaccinations during all pediatric
visits—well, sick, and follow-up—as well as by nurses can increase compliance. At the community level,
advertising, public messaging campaigns, and social media and text messaging educational materials
and reminders can inform parents of the benefits of vaccinations. Access to free vaccines and
opportunities for vaccination within the community, such as at day care facilities, walk-in clinics,
pharmacies, and financial aid offices can help remove financial barriers to vaccination.
Sudden Infant Death Syndrome
The leading cause of death of infants under the age of 1 is sudden infant death syndrome (SIDS)
(Bajanowski & Vennemann, 2017). SIDS is the diagnostic term used to describe the sudden, unexpected
death of an infant less than 1 year of age that occurs seemingly during sleep and remains unexplained
after a thorough investigation, including an autopsy and review of the circumstances of death and the
infant’s clinical history (Moon & Task Force on Sudden Infant Death Syndrome, 2016b).
What causes SIDS? It is believed to be the result of an interaction of factors, including an infant’s
biological vulnerability to SIDS coupled with exposure to a trigger or stressor that occurs during a critical
period of development (Moon & Task Force on Sudden Infant Death Syndrome, 2016a; Spinelli et al.,
2017). The first factor is unknown biological vulnerabilities, such as genetic abnormalities and mutations
and prematurity, that may place infants at risk for SIDS. A recent 10-year review of hundreds of SIDS
cases in Australia confirmed that, although the underlying cause of SIDS remains unknown, mutations
and genetic variants likely play a role (Evans et al., 2013). Second, environmental stressors or events that
might trigger SIDS include having the infant sleep on his or her stomach or side, use of soft bedding or
other inappropriate sleep surfaces (including sofas), bed-sharing, and exposure to tobacco smoke (Carlin
& Moon, 2017; Horne, 2019). One review of several hundred cases in the United Kingdom found that in
over a third of SIDS deaths the infants were co-sleeping with adults at the time of death (Blair et al.,
2006). Finally, there are developmental periods in which infants are most vulnerable to SIDS. Most cases
of SIDS occur between the 2nd and 5th month of life (Bajanowski & Vennemann, 2017). Therefore, it is
thought that SIDS is most likely to occur when the triple risks—biological vulnerability, triggering events,
and critical period of development—converge (Filiano & Kinney, 1994; Spinelli et al., 2017).
Ethnic differences appear in the prevalence of SIDS, with Native Americans and Blacks showing the
highest rates of SIDS in the United States, followed by non-Hispanic whites. Asian American and
Hispanic infants show lower rates of SIDS than white infants (Parks et al., 2017). Ethnic differences in
SIDS are likely due to differences in socioeconomic and lifestyle factors associated with SIDS, such as
lack of prenatal care, low rates of breastfeeding, maternal smoking, and low maternal age. Cultural
practices, such as adult–infant bed-sharing, providing infants with soft bedding, and placing the sleeping
baby in a separate room from caregivers increase SIDS risk (Colson et al., 2013; Parks et al., 2017;
Shapiro-Mendoza et al., 2014). Ethnic differences in SIDS are complex and influenced by context. In one
study of infants, Mexican American U.S.-born mothers had a 50% greater rate of SIDS than infants of
Mexican foreign-born mothers after controlling for factors associated with SIDS, including birth weight,
maternal age, education, marital status, prenatal care, and socioeconomic status (Collins et al., 2001).
Differences in acculturation and associated child care practices likely play a role in influencing SIDS risk,
but they are not well understood (Parks et al., 2017).
In the 1990s, SIDS declined dramatically after the American Academy of Pediatrics, based on data from
Europe, Australia, and the United States, recommended that infants be placed for sleep in a nonprone
position (i.e., a supine position: on their backs) as a strategy to reduce the risk of SIDS (Figure 4.6)
(Pediatrics, 1992). Initiated in 1992, the “Back to Sleep” campaign publicized the importance of nonprone
sleeping. Between 1992 and 2001, the SIDS rate declined dramatically in the United States and other
countries that implemented nonprone/supine sleeping campaigns (Bajanowski & Vennemann, 2017;
Bergman, 2015; Moon & Task Force on Sudden Infant Death Syndrome, 2016a), consistent with the
steady increase in the prevalence of supine sleeping. In addition to placing infants on their backs to
sleep, other recommendations for a safe sleep environment include the use of a firm sleep surface,
avoidance of soft bedding and infant overheating, and sharing a room with the infant without sharing a
bed (Horne, 2019). Avoid placing infants in sitting devices, such as car seats, strollers, and infant carriers,
for routine sleep. Couches and armchairs are extremely dangerous places for infants. SIDS poses grave
risks to infants, but the risks can be reduced.
Description
Figure 4.6 Trends in Sudden Unexpected Infant Death by Cause, 1990–2015
Sources: Centers for Disease Control and Prevention; National Center for
Health Statistics; National Vital Statistics System.
Thinking in Context: Intersectionality
1. What are some predictors of infant mortality?
2. To what degree are demographic factors, such as socioeconomic status, geographics, and
education, related to infant mortality?
3. What are some ways in which these demographic factors intersect with race and ethnicity? How, in
turn, might these intersections influence infant mortality?
4. How do you account for the finding that Black infants are most at risk for infant mortality regardless
of family income? What are some contextual factors that might influence the high rates of mortality
in Black infants?
Thinking in Context: Lifespan Development
1. Why are marasmus and kwashiorkor uncommon in the United States? What contextual factors
place children in developing nations at risk for these impairments? Compare these risk factors with
those for malnutrition and growth faltering for children in the United States.
2. How does the incidence of SIDS illustrate the interaction of biological and contextual risk factors?
Identify examples of contextual influences on the risk for SIDS, such as the home environment,
cultural practices, and policies and educational campaigns.
Thinking in Context: Applied Developmental Science
You overhear a parent say, “No, I don’t plan to vaccinate my child for measles, mumps, and rubella.”
What are some reasons why children are not vaccinated? Considering the benefits, common
misconceptions, and availability of vaccinations, how would you respond to their objections?
BRAIN DEVELOPMENT DURING INFANCY AND TODDLERHOOD
LEARNING OBJECTIVE
4.3 Summarize processes of brain development and the influence of experience on brain
development during infancy and toddlerhood.
Infants’ bodies grow rapidly but the most dramatic changes during infancy are much less visible. All of
the developments in infants’ physical and mental capacities are influenced by the changes that occur in
the brain. At birth, the brain is about 25% of its adult weight, and it grows rapidly throughout infancy,
reaching about 70% of its adult weight by 2 years of age (Lyall et al., 2015). As the brain develops, it
becomes larger and more complex.
The Neuron
The brain is made up of billions of cells called neurons. Neurons are specialized to communicate with
one another to make it possible for people to sense the world, think, move their bodies, and carry out
their lives. As shown in Figure 4.7, neurons have distinct structures that set them apart from other cells
and enable the communicative functions characteristic of neurons. Dendrites are branching receptors
that receive chemical messages (called neurotransmitters) from other neurons that are translated into an
electrical signal (Stiles, 2017). The axon is a long tube-like structure that extends from the neuron and
carries electrical signals to other neurons. Neurons do not touch. Instead, there are gaps between
neurons called synapses. Once the electrical signal reaches the end of the axon, it triggers the release of
a neurotransmitter that crosses the synapse to communicate with the dendrites of another neuron
(Carson, 2014). This process of neural transmission is how neurons communicate with other neurons.
Neurons also communicate with sensory and motor cells. Some axons synapse with muscle cells and are
responsible for movement. The dendrites of some neurons synapse with sensory cells, such as those in
the eyes or ears, to transfer sensory information, such as vision and hearing (Gibb & Kovalchuk, 2018).
Finally, axons are often coated with a fatty substance called myelin, which speeds the transmission of
electrical impulses and neurological function.
Figure 4.7 The Neuron
Processes of Neural Development
The first neurons form early in prenatal development, in the embryo’s neural tube, through a process
called neurogenesis. We are born with more than 100 billion neurons, more than we will ever need—and
more than we will ever have at any other time in our lives. Some of our neurons die, but neurogenesis
continues throughout life and new neurons are formed, although at a much slower pace than during
prenatal development (Kolb, 2020). As the brain develops, new neurons migrate along a network of glial
cells, a second type of brain cell that outnumbers neurons (Gibb & Kovalchuk, 2018). Glial cells nourish
neurons and move throughout the brain to provide a physical structure to the brain. As shown in Figure
4.8, neurons travel along glial cells to the location of the brain where they will function, often the outer
layer of the brain, known as the cortex, and glial cells instruct neurons to form connections with other
neurons (Kolb et al., 2016).
Figure 4.8 Glial Cell–Neuron Relationship
Source: Gasser & Hatten (1990).
At birth, the networks of neurons are simple, with few connections, or synapses, between neurons (Kolb
et al., 2016). Early in infancy, major growth takes place. Neurons and glial cells enlarge. The dendrites
grow and branch out, increasing synapses with other neurons, a process called synaptogenesis.
Synaptogenesis peaks in different brain regions at different ages (Remer et al., 2017). The most active
areas of synaptogenesis during the first 5 weeks of life are in the sensorimotor cortex and subcortical
parts of the brain, which are responsible for respiration and other essential survival processes. The visual
cortex develops very rapidly between 3 and 4 months and reaches peak density by 12 months of age.
The prefrontal cortex—responsible for planning and higher thinking—develops more slowly and is not
complete until early adulthood (Tamnes et al., 2017).
In response to exposure to stimulation from the outside world, the number of synapses initially rises
meteorically in the first year of life, and the dendrites increase 500% by age 2 (Schuldiner & Yaron,
2015). Cortical thickness peaks by 2 years of age, but surface area continues to develop throughout
childhood (Gilmore et al., 2018). Toddlers have more synapses than at any other point in life (Figure 4.9).
This explosion in connections in the early years of life means that the brain makes more connections
than it needs, in preparation to receive any and all conceivable kinds of stimulation (Kolb, 2020). Those
connections that are used become stronger and more efficient, while those unused eventually shrink,
atrophy, and disappear. This loss of unused neural connections is a process called synaptic pruning,
which can improve the efficiency of neural communication by removing “clutter”—excess, unused
connections. Little-used synapses are pruned in response to experience, an important part of
neurological development that leads to more efficient thought (Lyall et al., 2015).
Description
Figure 4.9 Synaptogenesis From Birth to Age 2
Source: Gilmore et al. (2018).
Another important process of brain development is myelination, in which glial cells produce and coat
the axons of neurons with a fatty substance called myelin. Myelination begins prenatally but accelerates
after birth (Gilmore et al., 2018). Myelination contributes to advances in neural communication because
axons coated with myelin transmit neural impulses more quickly than unmyelinated axons (Lebel &
Deoni, 2018). With increases in myelination, infants and children process information more quickly. Their
thought and behavior become faster, more coordinated, and complex (Chevalier et al., 2015).
Myelination proceeds most rapidly from birth to age 4, first in the sensory and motor cortex in infancy,
and continues through childhood into adolescence and early adulthood (Qiu et al., 2015).
We are born with more than 100 billion neurons, more than we will ever need
—and more than we will ever have at any other time in our lives.
Dennis Kunkel Microscopy/Science Source
The Cerebral Cortex
The wrinkled and folded outermost layer of the brain is known as the cortex. The cortex comprises
about 85% of the brain’s mass and develops throughout childhood, and some parts mature into early
adulthood.
The cortex is comprised of different structures with differing functions, located across four lobes. The
various parts of the brain work together, but as shown in Figure 4.10, each lobe is specialized to a certain
extent. The four lobes progress on different developmental timetables. The sensory and motor areas
tend to develop first. The frontal lobe, specifically a part called the prefrontal cortex, develops
throughout infancy, childhood, and adolescence, maturing into early adulthood (Hodel, 2018; Tamnes et
al., 2017). The prefrontal cortex is the part of the brain responsible for higher thought, such as planning,
goal setting, controlling impulses, and using cognitive skills and memory to solve problems.
In addition, the cortex is composed of two hemispheres that are joined by a thick band of neural fibers
known as the corpus callosum. Although all four lobes appear on both hemispheres, the hemispheres
are not identical. Over childhood, the right and left hemispheres become specialized to carry out
different functions, a process known as lateralization (Duboc et al., 2015). Each hemisphere of the brain
(and the parts of the brain that comprise each hemisphere) is specialized for particular functions and
becomes more specialized with experience. For most people, language is governed by the left
hemisphere.
Description
Figure 4.10 The Human Brain
Lateralization (“of the side,” in Latin) begins before birth and is influenced both by genes and by early
experiences (Young, 2016). In the womb, most fetuses face toward the left, freeing the right side of the
body, which permits more movement on that side and the development of greater control over the right
side of the body (Previc, 1991). In newborns, the left hemisphere tends to have greater structural
connectivity and efficiency than the right—more connections and pathways suggesting that they are
better able to control the right side of their bodies (Ratnarajah et al., 2013). Newborns tend to have
slightly better hearing from their right ear (Ari-Even Roth et al., 2016). Infants generally display a hand
preference, usually right, and their subsequent activity makes the hand more dominant because
experience strengthens the hand and neural connections and improves agility. In this way, over the
course of childhood one hemisphere becomes stronger and more adept, a process known as
hemispheric dominance. Most adults experience hemispheric dominance, usually with the left
hemisphere dominating over the right, making about 90% of adults in Western countries right-handed
(Duboc et al., 2015).
Experience and Brain Development
Stimulation and experience are key components needed to maximize neural connections and brain
development throughout life, but especially in infancy. Much of what we know about brain development
comes from studying animals. Animals raised in stimulating environments with many toys and
companions to play with develop brains that are heavier and have more synapses than do those who
grow up in standard laboratory conditions (Berardi et al., 2015). Likewise, when animals raised in
stimulating environments are moved to unstimulating standard laboratory conditions, their brains lose
neural connections. This is true for humans, too. Infants who are understimulated, such as those who
experience child maltreatment or who are reared in deprivation, such as in poor and understaffed
orphanages in developing countries, show deficits in brain volume as well as cognitive and perceptual
deficiencies that may persist into adolescence (Hodel, 2018; Nelson et al., 2019). In this way, infancy is
said to be a sensitive period for brain development, a period in which experience had a particularly
powerful role (Hensch, 2018).
The powerful role that experience plays in brain development can be categorized into two types. First,
the brain depends on experiencing certain basic events and stimuli at key points in time to develop
normally (Bick & Nelson, 2017; Hodel, 2018); this is referred to as experience-expectant brain
development. Experience-expectant brain development is demonstrated in sensory deprivation research
with animals. If animals are blindfolded and prevented from using their visual system for the first several
weeks after birth, they never acquire normal vision because the connections among the neurons that
transmit sensory information from the eyes to the visual cortex fail to develop; instead, they decay
(DiPietro, 2000). If only one eye is prevented from seeing, the animal will be able to see well with one
eye but will not develop binocular vision, the ability to focus two eyes together on a single object.
Similarly, human infants born with a congenital cataract in one eye (an opaque clouding that blocks light
from reaching the retina) will lose the capacity to process visual stimuli in the affected eye if they do not
receive treatment. Even with treatment, subtle differences in facial processing may remain (Maurer,
2017). Deprivation of sound has similar effects on the auditory cortex (Mowery et al., 2016).
Brain organization depends on experiencing certain ordinary events early in life, such as opportunities to
hear language, see the world, touch objects, and explore the environment (Kolb, 2020; Maurer, 2017). All
infants around the world need these basic experiences during specific times in development, known as
sensitive periods, to develop normally and it is difficult to repair errors that are the result of severe
deprivation and neglect (McLaughlin et al., 2017; Nelson et al., 2019).
A second type of development, experience-dependent brain development, refers to the growth that
occurs in response to learning experiences (Bick & Nelson, 2017). Experiences such as learning to stack
blocks or crawl on a slippery wood floor are unique to individual infants, and they influence what
particular brain areas and functions are developed and reinforced. Experience-dependent development
is the result of lifelong experiences that vary by individual based on contextual and cultural
circumstances (Kolb et al., 2014). Exposure to enriching experiences, such as interactive play with toy cars
and other objects that move; hands-on play with blocks, balls, and cups; and stimulating face-to-face
play can all enhance children’s development (Kolb, 2018). A longitudinal study that followed more than
350 infants from 5 to 24 months of age found that the quality of mother–infant interactions at 5 months
predicted greater brain activity in the prefrontal cortex at 10 and 24 months of age, suggesting that
parenting quality may contribute to brain development in infancy (Bernier et al., 2016). On the other
hand, exposure to deprivation and trauma can have lasting negative effects on brain development
(Harker, 2018).
The brain develops in response to experiences that are unique to each
individual, such as playing with specific toys or participating in social
interactions.
iStock/doble-d
Sleep and Brain Development
Whereas adults sleep approximately 8 hours each day, the typical neonate sleeps about 16 to 18 hours
each day. Sleep declines steadily. Six-month-old infants sleep about 12 hours (Figueiredo et al., 2016).
Infant rats, rabbits, cats, and rhesus monkeys also sleep much longer than adults, suggesting that sleep
serves a developmental function (Blumberg et al., 2014). Sleep promotes physical growth and
development (Tham et al., 2017). In adults, sleep is thought to permit the body to repair itself, as
indicated by increased cell production and the removal of metabolic wastes during sleep (Tononi &
Cirelli, 2014). Sleep is also associated with increases in connections among neurons (Krueger et al., 2016).
In adults, sleep is associated with memory consolidation and “cementing” memories, and sleep deficits
are associated with deficits in attention, memory, and learning (Chambers, 2017; Doyon et al., 2018;
Spencer et al., 2017). Rapid eye movement (REM) sleep, during which adults’ eyes flutter and dreaming
occurs, is particularly important for cognitive functioning (Lewis, 2017). Infants spend about half of their
sleep time in REM sleep, decreasing to about 20% in adulthood. REM sleep is thought to provide infants
with stimulation and promote brain development and cognitive growth (Friedrich et al., 2017; Tham et
al., 2017). Neonates with poor sleep patterns showed poor attention at 4 months and increased
distractibility at 18 months of age (Geva et al., 2016). Similar to findings with adults, one study found
that sleep was associated with memory formation in 3- to 8-month-old infants (Friedrich et al., 2017).
Sleep may have long-term effects on cognitive development. An examination of infants at 12 months of
age and again at 3 to 4 years old showed that lower-quality sleep in infancy was associated with
problems with attention and behavioral control in early childhood (Sadeh et al., 2015).
Sleeping serves a developmental function, yet young infants wake often (Mäkelä et al., 2018). The typical
newborn wakes every 2 hours to eat, and babies continue to require nighttime feedings until they are 4
or 5 months old. Many continue to wake at night. Cultures differ in infant sleep practices. Parents in the
United States typically look forward to the time when their infant will sleep through the night, view the
newborn’s unpredictable sleep pattern as something to endure, and believe infants to be in charge of
regulating their own sleep schedule (Schaik et al., 2020). In contrast, many European parents view
newborn sleep as part of normal development, do not intervene to shape newborn sleep cycles, but
provide regular routines to support infants’ natural rhythms. Children in Pacific-Asian countries tend to
sleep an hour less than those in North America, Europe, and Australia (Galland et al., 2012; Mindell et al.,
2010). Parental behavior influences infants’ sleep patterns. Infants are more likely to continue waking
overnight when their parents play with them during nighttime feedings, as stimulation and attention
may reinforce nighttime waking (Sadeh et al., 2015).
One hypothesis for infants’ increased time in sleep is that it provides
stimulation and promotes brain development.
iStock/Imagesbybarbara
Brain development is a multifaceted process that is not a result of maturational or environmental input
alone. Brains do not develop normally in the absence of a basic genetic code or in the absence of
essential environmental input. At all points in development, intrinsic and environmental factors interact
to support the increasingly complex and elaborate structures and functions of the brain.
Thinking in Context: Lifespan Development
Sleep plays an important role in brain development, but contextual factors can influence the amount
and quality of infants’ sleep.
1. How might infants’ homes, families, and communities influence their sleep? Identify environmental
factors that might influence their sleep quality.
2. To what degree might these factors also influence infants’ development while awake?
Thinking in Context: Biological Influences
1. Marta hopes to promote her baby’s brain development. Explain the processes that influence
infants’ brain development and provide advice to help Marta promote her infant’s development.
2. Discuss the role of experience in brain development. Considering two ways in which experience
influences brain development, what advice do you give to parents who want to promote their
infants’ development?
EARLY LEARNING CAPACITIES
LEARNING OBJECTIVE
4.4 Compare infants’ early learning capacities for habituation, classical conditioning, operant
conditioning, and imitation.
Can newborns learn? If we define learning as changing behavior in response to experience, certainly:
Animals and even insects learn. Yet infants were once believed to be born incapable of sensing and
understanding the physical world around them. Most new parents will quickly tell you that this is far
from the truth. At birth, and even before, neonates can perceive their physical world and have powerful
capacities for learning about it.
Habituation
Less than 1 day old, cradled next to his mother in the hospital maternity center, Tommy is already
displaying the earliest form of learning. He no longer cries each time he hears the loud beep made by
the machine that reads his mother’s blood pressure. This type of learning is called habituation; it occurs
when repeated exposure to a stimulus results in the gradual decline in the intensity, frequency, or
duration of a response (Figure 4.11). All animals and humans are programmed to learn. Even before
birth, humans demonstrate habituation, as early as 22 to 24 weeks’ gestation (Hepper, 2015). Fetuses 27
to 36 weeks old demonstrate habituation to vibration as well as auditory stimuli, such as the sound of a
tone. Initially, the fetus moves in response to the vibration, suggesting interest in a novel stimulus. After
repeated stimulation, the fetus no longer responds to the stimulus, indicating that it has habituated to it
(McCorry & Hepper, 2007; Muenssinger et al., 2013). Not only can the fetus habituate to stimuli, but it
can recall a stimulus for at least 24 hours (van Heteren et al., 2000).
Habituation improves with development. The performance of fetuses on habituation tasks improves with
gestational age (James, 2010). After birth, habituation is often measured by changes in an infant’s heart
rate and in attention or looking at a stimulus (Domsch et al., 2010). Younger infants require more time to
habituate than older infants (Kavšek & Bornstein, 2010). Five- to 12-month-old babies habituate quickly
—even after just a few seconds of sustained attention—and in some cases, they can recall the stimulus
for weeks, such as recalling faces that they have encountered for brief periods of time (Richards, 1997).
Description
Figure 4.11 Habituation
Source: Habituation graph from Visual Development Web unit by Marcela
Salamanca and Donald Kline, University of Calgary. Reprinted by permission
of the authors.
Neural development, specifically the development of the prefrontal cortex, is thought to underlie agerelated gains in habituation skill (Nakano et al., 2009). As the brain matures, infants process information
more quickly and learn more about stimuli in fewer exposures. Younger infants and those with low
birthweight require more time to habituate than do older and more fully developed infants (Kavšek &
Bornstein, 2010; Krafchuk et al., 1983; Rovee-Collier, 1987). Fetuses with more mature nervous systems
require fewer trials to habituate than do those with less well developed nervous systems, even at the
same gestational age (Morokuma et al., 2004). Fetal habituation predicts measures of information
processing ability at 6 months of age (Gaultney & Gingras, 2005).
There are also individual differences in habituation. Some infants habituate quickly and recall what they
have learned for a long time. Others require many more exposures to habituate and quickly forget what
they have learned. The speed at which infants habituate is associated with cognitive development when
they grow older. Infants who habituate quickly during the first 6 to 8 months of life tend to show more
advanced capacities to learn and use language during the second year of life (Tamis-LeMonda et al.,
1989). Rapid habituation is also associated with higher scores on intelligence tests in childhood (Kavšek,
2004). The problem-solving skills measured by intelligence tests tap information processing skills such as
attention, processing speed, and memory—all of which influence the rate of habituation (McCall, 1994).
Innate learning capacities permit young infants to adapt quickly to the world, a skill essential for survival.
Researchers use these capacities to study infant perception and cognition (Aslin, 2014). To examine
whether an infant can discriminate between two stimuli, a researcher presents one until the infant
habituates to it. Then a second stimulus is presented. If dishabituation, or the recovery of attention,
occurs, it indicates that the infant detects that the second stimulus is different from the first. If the infant
does not react to the new stimulus by showing dishabituation, it is assumed that the infant does not
perceive the difference between the two stimuli. The habituation method is very useful in studying infant
perception and cognition and underlies many of the findings discussed later in this chapter.
Classical Conditioning
In addition to their capacity to learn by habituation, infants are born with a second powerful tool for
learning. They can learn through association. Classical conditioning entails making an association
between a neutral stimulus and an unconditioned stimulus that triggers an innate reaction. Eventually,
the neutral stimulus (now conditioned stimulus) produces the same response as the unconditioned
stimulus.
Newborns demonstrate classical conditioning. When stroking the forehead was paired with tasting sugar
water, 2-hour-old infants were conditioned to suck in response to having their heads stroked (Blass et
al., 1984). Let’s look at this example more closely. Sugar water is an unconditioned stimulus as it naturally
evokes the unconditioned response of sucking in infants. Touching or stroking the forehead yielded no
response from the 2-hour-old infants; it was a neutral stimulus. When the researcher paired the neutral
stimulus (stroke) with the unconditioned stimulus (sugar water), infants soon showed the conditioned
response. That is, they associated the stroking with sugar water and thereby responded to the stroke
with sucking movements.
Similarly, Lipsitt and Kaye (1964) paired a tone with the presentation of a nipple to 2- and 3-day-old
infants. Soon, the infants began to make sucking movements at the sound of the tone. Sleeping
neonates can be conditioned to respond to a puff of air to the eye (Tarullo et al., 2016). Even premature
infants can demonstrate associative learning, although at slower rates than full-term infants (Herbert et
al., 2004). Research with chimpanzee fetuses has shown that they display classical conditioning before
birth (Kawai, 2010). It is likely that the human fetus can as well. Although classical conditioning is innate,
neurological damage can hinder infants’ abilities to learn by association. Infants with fetal alcohol
syndrome (FAS) require much more time than other infants to associate eye blinking with external
stimuli, such as sounds (Cheng et al., 2016).
Newborns tend to require repeated exposures to conditioning stimuli because they process information
slowly (Little et al., 1984). As infants grow older, classical conditioning occurs more quickly and to a
broader range of stimuli. In a classic study, Watson and Raynor (1920) paired a white rat with a loud
banging noise to evoke fear in an 11-month-old boy known as Little Albert. Repeated pairings of the
white rat with the loud noise made Albert cry even when the rat was presented without the noise. In
other words, Little Albert was conditioned to associate the neutral stimulus with the conditioned
stimulus. Little Albert demonstrated fear in response to seeing the rat, indicating that emotional
responses can be classically conditioned. Our capacities to learn through classical conditioning are
evident at birth—and persist throughout life.
Operant Conditioning
At birth, babies can learn to engage in behaviors based on their consequences, known as operant
conditioning. Behaviors increase when they are followed by reinforcement and decrease when they are
followed by punishment. Newborns will change their rate of sucking on a pacifier, increasing or
decreasing the rate of sucking, to hear a tape recording of their mother’s voice, a reinforcer (Moon et al.,
1993). Reinforcers are experienced as pleasurable. Infants (and people of all ages) change their behavior
to experience reinforcement, in this example, changing the rate of sucking on a pacifier to hear the
mother’s voice. Other research shows that newborns will change their rate of sucking to see visual
designs or hear human voices that they find pleasing (Floccia et al., 1997). Premature infants and even
third-trimester fetuses can be operantly conditioned (Thoman & Ingersoll, 1993). A 35-week-old fetus
will change its rate of kicking in response to hearing the father talk against the mother’s abdomen
(Dziewolska & Cautilli, 2006).
As infants develop, they process information more quickly and require fewer trials pairing behavior and
consequence to demonstrate operant conditioning. It requires about 200 trials for 2-day-old infants to
learn to turn their heads in response to a nippleful of milk, but 3-month-old infants require about 40
trials, and 5-month-olds require fewer than 30 trials (Papousek, 1967). Infants’ early capacities for
operant conditioning imply that they are active and responsive to their environments and adapt their
behavior from birth.
Imitation
Toddler Tula puts a bowl on her head and pats it just as she watched her older sister do yesterday.
Imitation is an important way in which children and adults learn. Can newborns imitate others? Believe it
or not, some researchers argue that newborns have a primitive ability to learn through imitation. In a
classic study, 2-day-old infants mimicked adult facial expressions, including sticking out the tongue,
opening and closing the mouth, and sticking out the lower lip (Meltzoff & Moore, 1977) (Figure 4.12).
The prevalence and function of neonate imitation are debated (Suddendorf et al., 2013). Some studies
have failed to replicate this ability and have suggested that tongue protruding simply reflects a general
spontaneous newborn behavior, that it reflects arousal and that neonate imitation is not
developmentally similar to later social imitation (Keven & Akins, 2017; Oostenbroek et al., 2016; Vincini
et al., 2017). Others have confirmed that newborns from several ethnic groups and cultures display early
capacities for imitation (Meltzoff & Kuhl, 1994; Nadel & Butterworth, 1999). In one study, newborns
made corresponding mouth movements to both vowel and consonant vocal models; when the adult
model made an sound, newborns opened their mouths, and when the model made an sound,
newborns clutched their mouths (Chen et al., 2004). Studies that require infants to imitate several
behaviors in response to different stimuli suggest that neonate imitation is not simply an arousal
response (Nagy et al., 2013).
a
m
Description
Figure 4.12 Neonate Imitation
Source: Meltzoff & Moore (1977).
Newborns mimic facial expressions, but they are simply carrying out an innate program thought to be
controlled by the mirror neuron system, located in the premotor cortex (Binder et al., 2017). The mirror
neuron system, an inborn capacity to make associations and respond to the actions of others by
mirroring their actions in our own neural circuits, is apparent in both newborn humans and monkeys
(Cook et al., 2014; Olsen, 2006; Shaw & Czekóová, 2013). The ability to copy others’ actions likely serves
an evolutionarily adaptive purpose in humans, perhaps to aid the development of social communication
(Tramacere et al., 2017). Newborns do not understand imitation; rather, the action of mirror neurons
naturally syncs their body movements with the model. The regulatory mechanisms to inhibit imitative
responding develop during infancy (Rizzolatti et al., 2008).
Thinking in Context: Applied Developmental Science
1. What do early learning capacities mean for parenting? What information about habituation,
conditioning, or imitation should parents be aware of, if any? Why?
2. How might these learning principles be applied to address childrearing issues, such as how to get
infants to sleep through the night or how to introduce new foods?
SENSATION AND PERCEPTION DURING INFANCY AND TODDLERHOOD
LEARNING OBJECTIVE
4.5 Describe infants’ developing sensory abilities.
Meeting the pediatrician for the first time in her young life, newborn Kerry stared intently at the object
the doctor held about 6 inches from her face. “I think she sees it!” said her surprised mother. “She most
certainly does,” said the doctor. “Even as a newborn, your Kerry can sense the world better than you
realize.” Newborns can see, hear, smell, taste, and respond to touch, but it is unclear how they perceive
sensory stimuli.
Developmental researchers draw a distinction between sensation and perception. Sensation occurs
when our senses detect a stimulus. Our senses, the eyes, ears, tongue, nostrils, and skin, convert stimuli
—such as visual, auditory, taste, olfactory (smell), and tactile (touch)—into electrical impulses that travel
on sensory nerves to the brain where they are processed. Perception refers to the sense our brain makes
of the stimulus and our awareness of it. The newborn is equipped with a full range of senses, ready to
experience the world. They can both detect and perceive stimuli, but many of their abilities are immature
relative to those of adults. Yet infants’ sensory abilities develop rapidly, achieving adult levels within the
first year of life (Johnson & Hannon, 2015).
Methods for Studying Infant Perception
preferential looking tasks
How do researchers study infant perception? The simplest method is through
,
experiments designed to determine whether infants prefer to look at one stimulus or another. For
example, consider an array of black and white stripes. As shown in Figure 4.13, an array with more stripes
(and therefore, many more narrow stripes) tends to appear gray rather than black and white because the
pattern becomes more difficult to see as the stripes become more narrow. Researchers determine
infants’ visual acuity, sharpness of vision or the ability to see, by comparing infants’ responses to stimuli
with different frequencies of stripes because infants who are unable to detect the stripes lose interest in
the stimulus and look away from it.
Figure 4.13 Visual Acuity
Source:Leat et al. (2009).
Another method of studying infant perception relies on infants’ capacity for habituation, a gradual
decline in the intensity, frequency, or duration of a response to an unchanging stimulus. To examine
whether an infant can discriminate between two stimuli, a researcher presents one until the infant
habituates to it. Then a second stimulus is presented. If dishabituation, or the recovery of attention,
occurs, it indicates that the infant detects that the second stimulus is different from the first. If the infant
does not react to the new stimulus by showing dishabituation, it is assumed that the infant does not
perceive the difference between the two stimuli. The habituation method is very useful in studying infant
perception and cognition, and it underlies many of the findings discussed in this chapter.
Operant conditioning is the basis for a third method researchers use to study perception in infants.
Recall that operant conditioning entails learning behaviors based on their consequences, whether they
are followed by reinforcement or punishment. Behaviors increase when they are followed by
reinforcement and decrease when they are followed by punishment. Research employing this method
has shown that newborns will change their rate of sucking on a pacifier, increasing or decreasing the
rate of sucking, in order to hear a tape recording of their mother’s voice, a reinforcer (Moon et al., 1993).
Other research shows that newborns will change their rate of sucking to see visual designs or hear
human voices that they find pleasing (Floccia et al., 1997).
Vision
It is impossible to know whether the fetus has a sense of vision, but the fetus responds to bright light
directed at the mother’s abdomen as early as 28 weeks’ gestation (Johnson & Hannon, 2015). At birth,
vision is the least developed sense, but it improves rapidly. Newborn visual acuity is approximately
20/400 (Farroni & Menon, 2008). Preferential looking studies show that infants reach adult levels of
visual acuity between 6 months and 1 year of age (Mercuri et al., 2007). Improvement in vision is due to
the increasing maturation of the structures of the eye and the visual cortex, the part of the brain that
processes visual stimuli.
Face Perception
Newborns are born with preferences for particular visual stimuli. Newborns prefer to look at patterns,
such as a few large squares, rather than a plain stimulus such as a black or white oval shape (Fantz,
1961). Newborns also prefer to look at faces, and the preference for faces increases with age (Frank et
al., 2009). Face processing is influenced by experience with faces (Quinn et al., 2018). Infants generally
tend to see more female than male faces and more own- than other-race faces (Sugden et al., 2014).
Between birth and 3 months, infants begin to prefer to look at and can more easily recognize female
faces as compared with male faces, when their caregivers are female; but they do not show similar
preferences when their caregivers are male (Bayet et al., 2015; Rennels & Kayl, 2017).
Infants show similar preferences and abilities to discriminate same-race faces over other-race faces. That
is, between approximately 3 and 9 months of age, infants tend to prefer and are better able to
distinguish faces of frequently experienced groups, typically faces of members of their own race.
However, differentiation of faces from within unfamiliar groups, such as other races, becomes more
difficult with age (Markant & Scott, 2018). After about 9 months infants show difficulty discriminating
among unfamiliar faces, such as other-race faces. This decline in sensitivity to discriminate faces within
unfamiliar groups is called perceptual narrowing (Scott et al., 2007). Experience influences perceptual
narrowing. Specifically, babies who are extensively exposed to other-race faces (e.g., through adoption,
training, or living in racially diverse communities) show less perceptual narrowing (Ellis et al., 2017).
Some researchers speculate that early perceptual differences in infancy may be associated with the
emergence of implicit racial bias in childhood, but more research is needed to understand the social
implications of same- and other-race face recognition (Lee et al., 2017; Quinn et al., 2019).
Object Exploration
How infants explore visual stimuli changes with age (Colombo et al., 2015). Until about 1 month of age,
infants tend to scan along the outer perimeter of stimuli. When presented with a face, the infant’s gaze
will scan along the hairline and not move to the eyes and mouth. This is known as the externality effect
because infants scan along the outer contours of complex visual stimuli. By 6 to 7 weeks of age, infants
study the eyes and mouth, which hold more information than the hairline, as shown in Figure 4.14
(Hunnius & Geuze, 2004). Similarly, the ability to follow an object’s movement with the eyes, known as
visual tracking, is very limited at birth but improves quickly. By 2 months of age, infants can follow a
slow-moving object smoothly, and by 3 to 5 months, their eyes can dart ahead to keep pace with a fastmoving object (Agyei et al., 2016; Richards & Holley, 1999). The parts of the brain that process motion in
adults are operative in infants by 7 months of age (Weaver et al., 2015).
Description
Figure 4.14 Externality Effect and Face Perception
Source: Adapted from Shaffer (2002) and Salapatek (1975).
Color Vision
Like other aspects of vision, color vision improves with age. Newborns see color, but they have trouble
distinguishing among colors. That is, although they can see both red and green, they do not perceive
red as different from green. Early visual experience with color is necessary for normal color perception to
develop (Colombo et al., 2015; Sugita, 2004). Habituation studies show that by 1 month of age, infants
can distinguish between red, green, and white (Teller, 1997). By 2 to 3 months of age, infants are as
accurate as adults in discriminating the basic colors of red, yellow, and blue (Matlin & Foley, 1997; Teller,
1998). By 3 to 4 months of age, infants can distinguish many more colors as well as distinctions among
closely related colors (Bornstein & Lamb, 1992; Haith, 1993). Seven-month-old infants detect color
categories similar to those of adults; they can group slightly different shades (e.g., various shades of
blue) into the same basic color categories as adults do (Clifford et al., 2009).
Newborns see color but they have trouble distinguishing among colors.
Phanie/Alamy Stock Photo
Depth Perception
Depth perception is the ability to perceive the distance of objects from each other and from ourselves.
Depth perception is what permits infants to successfully reach for objects and, later, to crawl without
bumping into furniture. By observing that newborns prefer to look at three-dimensional objects than
two-dimensional figures, researchers have found that infants can perceive depth at birth (Slater et al.,
1984). Three- to 4-week-old infants blink their eyes when an object is moved toward their face, as if to
hit them, suggesting that they are sensitive to depth cues (Kayed et al., 2008; Náñez & Yonas, 1994).
Infants learn about depth by observing and experiencing motion.
visual cliff
A classic series of studies using an apparatus called the
demonstrated that crawling influences
how infants perceive depth. The visual cliff, as shown in Figure 4.15, is a Plexiglas-covered table bisected
by a plank so that one side is shallow, with a checkerboard pattern right under the glass, and the other
side is deep, with the checkerboard pattern a few feet below the glass (Gibson & Walk, 1960). In this
classic study, crawling babies readily moved from the plank to the shallow side but not to the deep side,
even if coaxed by their mothers, suggesting that they perceive the difference in depth (Walk, 1968). The
more crawling experience infants have, the more likely they are to refuse to cross the deep side of the
visual cliff (Bertenthal et al., 1984).
Figure 4.15 Visual Cliff
Does this mean that babies cannot distinguish the shallow and deep sides of the visual cliff until they
crawl? No, because even 3-month-old infants who are too young to crawl distinguish shallow from deep
drops. When placed face down on the glass surface of the deep side of the visual cliff, 3-month-old
infants became quieter and showed a decrease in heart rate compared with when they were placed on
the shallow side of the cliff (Dahl et al., 2013). The young infants can distinguish the difference between
shallow and deep drops but do not yet associate fear with deep drops.
As infants gain experience crawling, their perception of depth changes. Newly walking infants avoid the
cliff’s deep side even more consistently than do crawling infants (Dahl et al., 2013; Witherington et al.,
2005). A new perspective on the visual cliff studies argues that infants avoid the deep side of the cliff not
out of fear but simply because they perceive that they are unable to successfully navigate the drop; fear
might be conditioned through later experiences, but infants are not naturally fearful of heights (Adolph
et al., 2014 ).
Hearing
The capacity to hear develops in the womb; in fact, hearing is the most well-developed sense at birth.
Newborns are able to hear about as well as adults (Northern et al., 2014). Shortly after birth, neonates
can discriminate among sounds, such as tones (Hernandez-Pavon et al., 2008). By 3 days of age, an
infant will turn their head and eyes in the general direction of a sound, and this ability to localize sound
improves over the first 6 months (Clifton et al., 1994; Litovsky & Ashmead, 1997).
As we will discuss in Chapter 5, the process of learning language begins at birth, through listening.
Newborns are attentive to voices and can detect their mother's voice. Newborns only 1 day old prefer to
hear speech sounds over similar-sounding nonspeech sounds (May et al., 2018). Newborns can perceive
and discriminate nearly all sounds in human languages, but from birth they prefer to hear their native
language (Kisilevsky, 2016). Brain activity in the temporal and left frontal cortex in response to auditory
stimuli indicates that newborns can discriminate speech patterns, such as differences in cadence among
languages, suggesting an early developing neurological specialization for language (Gervain et al., 2008;
Gervain & Mehler, 2010).
Touch
Compared with vision and hearing, we know much less about the sense of touch in infants. In early
infancy, touch, especially with the mouth, is a critical means of learning about the world (Piaget,
1936/1952). The mouth is the first part of the body to show sensitivity to touch prenatally and remains
one of the most sensitive areas to touch after birth.
Touch, specifically a caregiver’s massage, can reduce stress responses in preterm and full-term neonates
and is associated with weight gain in newborns (Álvarez et al., 2017). Skin-to-skin contact with a
caregiver, as in kangaroo care (see Chapter 3), has an analgesic effect, reducing infants’ pain response to
being stuck with a needle for vaccination (Pandita et al., 2018). Although it was once believed that
newborns were too immature to feel pain, we now know that the capacity to feel pain develops even
before birth. In one study, fetuses as early as 24 weeks of age observed with sophisticated ultrasound
technology showed facial expressions suggesting distress or pain in response to a needle prick
(Reissland et al., 2013).
The neonate’s capacity to feel pain has influenced debates about infant circumcision, the procedure of
removing the foreskin of the penis. Although it is uncommon throughout much of the world, about
three-quarters of males in the United States are circumcised (Morris et al., 2016). Interestingly, there are
geographic patterns whereby circumcision is nearly twice as common in the Midwest as in the West
(Figure 4.16) (Owings et al., 2013). In recent years, circumcision has come under increasing scrutiny
within the United States as some charge that it places the newborn under great distress. Newborns show
many indicators of stress during circumcision, such as a high-pitched wail, flailing, grimacing, and
dramatic rises in heart rate, blood pressure, palm-sweating, pupil dilation, muscle tension, and cortisol
levels (Paix & Peterson, 2012).
Description
Figure 4.16 Rates of Circumcision Performed, 1979–2010
Notes: Rates represent circumcisions performed during the birth
hospitalization. Circumcision is identified by the International Classification of
Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) procedure code
64.0.
Source: Owings et al. (2013).
The benefits and whether they warrant the procedure are hotly debated (Beal, 2017; Freedman, 2016).
The medical benefits of circumcision include reduced risk of having urinary tract infections, developing
penile cancer, and acquiring HIV (American Academy of Pediatrics (AAP) Task Force on Circumcision
Policy, 1999); American Medical Association, 1999; Morris et al., 2017). But these are relatively rare
conditions and the evidence regarding HIV transmission comes from research with adult men in Africa,
which may not apply to infants in Western industrialized countries (Alanis & Lucidi, 2004).
In 1999, both the American Medical Association (AMA) and American Academy of Pediatrics (AAP)
joined medical associations in Canada, Europe, and Australia in concluding that the benefits of
circumcision are not large enough to recommend routine circumcision; instead, it is a parental decision.
In 2012, the AAP revised the recommendation to note that, although it is a parental decision, the
benefits of circumcision justify providing access to the procedure (by insurance companies) to families
who choose it. Critics and representatives of medical associations in Canada, Australia, and several
European countries countered that the revised recommendation was not based on medical evidence but
instead reflected cultural bias to support social practices common in the United States (Frisch et al.,
2013).
Ultimately, parental decisions about circumcision are influenced by cultural, religious, and social factors
(Freedman, 2016). In Jewish cultures, a boy is circumcised on the eighth day after birth in a ritual
celebration known as a bris, in which the boy is welcomed as a member of the community. Parents’
decisions are also influenced by social factors such as whether the father is circumcised and the desire
that the child resemble his peers (Bo & Goldman, 2008). The decision is complicated, as parents weigh
health risks and benefits with religious and cultural beliefs and personal desires, to determine what is
best for their child. When circumcision is conducted, analgesia (pain relief in which the newborn remains
conscious) is safe and effective in reducing the pain associated with circumcision (American Academy of
Pediatrics, 2012). Treatment as simple as administering a sugar solution to infants aids in pain
management (Matsuda, 2017).
An 8-day-old Jewish boy is circumcised as part of a religious ceremony called
a bris.
PS-I/Alamy Stock Photo
Smell and Taste
Smell and taste receptors are functional in the fetus, and preferences are well developed at birth
(Bloomfield et al., 2017). Just hours after birth, newborns display facial expressions signifying disgust in
response to odors of ammonia, fish, and other scents that adults find offensive (Steiner, 1979). Within
the first days of life, newborns detect and recognize their mother’s odor (Macfarlane, 1975; Marin et al.,
2015). Infants are calmed by their mother’s scent. Newborns who smelled their mother’s odor displayed
less agitation during a heel-stick test and cried less afterward than infants presented with unfamiliar
odors (Rattaz et al., 2005). Familiar scents are reinforcing and can reduce stress responses in infants
(Schaal, 2017). The scent of breast milk can slow heart rate in premature neonates who are under stress
(Neshat et al., 2016).
Infants show innate preferences for some tastes (Ross, 2017). Both bottle-fed and breastfed newborns
prefer human milk—even milk from strangers—to formula (Marlier & Schaal, 2005). Newborns prefer
sugar to other substances, and a small dose of sugar can serve as an anesthetic, distracting newborns
from pain (Forestell, 2017). Experience can modify taste preferences, beginning before birth: Fetuses are
exposed to flavors in amniotic fluid that influence their preferences after birth (Beauchamp & Mennella,
2011; Forestell, 2016). In one study, the type of formula fed to infants influenced their taste preferences
at 4 to 5 years of age (Mennella & Beauchamp, 2002). Infants who were fed milk-based formulas and
protein-based formulas were more likely to prefer sour flavors at 4 to 5 years of age compared with
infants who were fed soy-based formulas, who, in turn, were more likely to prefer bitter flavors.
Intermodal Perception
All stimuli we encounter involve more than one type of sensory information. For example, we see a dog
but we also hear its bark. Not only are infants able to sense in multiple modalities, but they are able to
coordinate their senses. Intermodal perception is the process of combining information from more than
one sensory system (Johnson & Hannon, 2015). Sensitivity to intermodal relations among stimuli is
critical to perceptual development and learning—and this sensitivity emerges early in life (Lewkowicz et
al., 2010). That is, infants expect vision, auditory, and tactile information to occur together (Sai, 2005).
Newborns turn their heads and eyes in the direction of a sound source, suggesting that they intuitively
recognize that auditory and visual information co-occur and provide information about spatial location
(Newell, 2004).
Newborns show a preference for viewing their mother’s face at 72, 12, and even just 4 hours after birth
(Pascalis et al., 1995). It was once believed that infants’ preference for their mother’s face was innate. Are
infants born knowing their mother’s face? In one study, neonates were able to visually recognize their
mother’s face only if the face was paired with their mother’s voice at least once after birth (Sai, 2005).
Thus, intermodal perception is evident at birth because neonates can coordinate auditory (voice) and
visual stimuli (face) to recognize their mother. They quickly remember the association and demonstrate a
preference for her face even when it is not paired with her voice.
Infants integrate touch and vision very early in life. In one classic study, 1-month-old infants were
presented with a smooth-surfaced pacifier or one with nubs on it. After exploring it with their mouths,
the infants were shown two pacifiers—one smooth and one nubbed. The infants preferred to look at the
shape they had sucked, suggesting that they could match tactile and visual stimuli (Meltzoff & Borton,
1979). In another example, 8- to 31-day-old infants fitted with special goggles were presented with a
virtual object created by a shadow caster (Bower et al., 1970). The virtual object was an illusory object
that could be seen by the infant but not touched. When the infant reached for the object, his or her
hand felt nothing and flailed through the air. Infants exposed to the virtual object attempted to reach for
it and became distressed when they did not feel it, suggesting that vision and touch are integrated and
infants expect to feel objects that they can see and reach.
Moreover, fMRI research suggests that in response to intermodal stimuli, very young infants (11–36 days
old) show activity in similar sensory regions of the brain as adults (Sours et al., 2017). When given soft
brush strokes to the skin of their leg, 11- to 36-day-old infants show similar neural responses as children
and adults in areas linked with sensory, social, and affective processing (Tuulari et al., 2019). Infants’ early
sensitivity to touch and its links with socio-affective brain regions may play an important role in
development.
Infants’ sensitivity to touch and their ability to integrate auditory with tactile information may aid
learning. When 5- to 7-month-old infants listened to abstract patterns of tones while being touched on
the knee or elbow, they were more likely to remember auditory sequences when the accompanying
touches matched the auditory pattern, suggesting that social touch can influence how infants process
stimuli and learn (Lew-Williams et al., 2019).
Touch, particularly caregivers’ touch, promotes learning. In one study, 4-month-old infants habituated to
a face while their forehead was either stroked with a soft paintbrush, stroked by a caregiver, or not
stroked. The infants who were stroked by caregivers looked significantly longer than their peers when
shown a new face, suggesting that caregiver touch promoted learning (Della Longa, 2019). Social touch
may play a special role in facilitating sensory integration and learning.
Although young infants show impressive capacities to integrate visual and tactile information, these
senses are not completely integrated at birth. Newborns can visually recognize an object previously held
but not seen, but they cannot tactually recognize an object previously seen and not held, suggesting
that intermodal relations among senses are not bidirectional at birth (Sann & Streri, 2007). Instead,
development may be triggered by experience.
Infant–Context Interactions and Perceptual Development
We have seen that individuals are embedded in and interact dynamically with their context.
Developmental scientists James and Eleanor Gibson applied ecological theory to perceptual
development, emphasizing that perception arises through interactions with the environment (Adolph &
Kretch, 2015). Rather than individuals collecting small pieces of sensory information to build a
representation of the world, the Gibsons argued that the environment itself provides all the information
needed. Individuals perceive the environment directly, without constructing or manipulating sensory
information.
Perception arises from action. Infants actively explore their environment with their eyes, moving their
heads and, later, reaching their hands and, eventually, crawling. Perception provides the information
infants need to traverse their environment. Through their exploration, infants perceive affordances—the
nature, opportunities, and limits of objects (Gibson & Pick, 2000). The features of objects tell infants
about their affordances and their possibilities for action, such as whether an object is squeezable,
mouthable, catchable, or reachable.
Infants explore their environment, not randomly but rather systematically searching to discover the
properties of the things around them (Savelsbergh et al., 2013). From this perspective, perception arises
from action, just as it influences action (Gibson, 1979). Exploration and discovery of affordances depend
on infants’ capacities for action, which are influenced by their development, genetics, and motivation. A
large pot might offer a 10-year-old child the possibility of cooking because the child has learned this
capacity (has observed cooking, for example) and can perceive this affordance (or use) of the pot. In
contrast, an 18-month-old infant may perceive very different affordances of the pot, such as a drum to
bang or a bucket to fill, based on the child’s capacities. We naturally perceive affordances, such as
knowing when a surface is safe for walking, by sensing information from the environment and
coordinating it with our body sensations, such as our sense of balance (Kretch et al., 2014). In this way,
our perception of affordances, the opportunities for exploration, influences how we move and interact
within our environments, and ultimately our opportunities for learning (Adolph & Kretch, 2015).
Thinking in Context: Applied Developmental Science
How might parents and caregivers design caregiving environments that are tailored to infants’ early
learning and sensory capacities and stimulate development? What advice would you give on how to
design such an environment for a newborn? For a 6-month-old infant?
Thinking in Context: Lifespan Development
Intermodal perception and the perception of affordances illustrate how infants are active participants in
their own development (Chapter 1). Discuss this statement with examples.
Thinking in Context: Biological Influences
Consider visual development from the perspective of evolutionary developmental psychology, as passed
through generations by natural selection (Chapter 1).
1. How might patterns of visual development, such as face perception, object exploration, color
vision, and depth perception, illustrate adaptive functioning from an evolutionary perspective?
2. Might the nature of early, immature visual functioning have an adaptive purpose?
3. How might the timing and transition to more mature visual function serve infants’ adaptation?
MOTOR DEVELOPMENT DURING INFANCY AND TODDLERHOOD
LEARNING OBJECTIVE
4.6 Contrast maturation, contextual, and dynamic systems explanations for motor development in
infancy and toddlerhood.
Newborns are equipped to respond to the stimulation they encounter in the world. The earliest ways in
which infants adapt are through the use of their reflexes, involuntary and automatic responses to stimuli
such as touch, light, and sound. Each reflex has its own developmental course (Payne & Isaacs, 2020).
Some disappear early in life and others persist throughout life (Table 4.1). Infants show individual
differences in how reflexes are displayed, specifically the intensity of the response. Preterm newborns
show reflexes suggesting a more immature neurological system than full-term newborns (Barros et al.,
2011). The absence of reflexes may signal neurological deficits.
Table 4.1 Newborn Reflexes
Name of
Reflex
Palmar
grasp
Response
Developmental Course
Curl fingers around objects that touch the palm
Birth to about 4 months,
when it is replaced by
voluntary grasp
Name of
Reflex
Rooting
Response
Developmental Course
Turn head and tongue toward stimulus when cheek is
touched
Disappears over the first
few weeks of life and is
replaced by voluntary head
movement
Birth to about 6 months
Birth to about 5 to 7
months
Sucking
Moro
Suck on objects placed into the mouth
Startle response in reaction to loud noise or sudden change
in the position of the head, results in throwing out arms,
arching the back, and bringing the arms together as if to
grasp something
Babinski
Fans and curls the toes in response to stroking the bottom of
the foot
Stepping Makes stepping movements as if to walk when held upright
with feet touching a flat surface
Swimming Holds breath and moves arms and legs, as if to swim, when
placed in water
Birth to about 8 to 12
months
Birth to about 2 to 3
months
Birth to about 4 to 6
months
Gross Motor Development
Gross motor development refers to the ability to control the large movements of the body, actions that
help us move around in our environment. Like physical development, motor skills evolve in a predictable
sequence. By the end of the first month of life, most infants can reach the first milestone, or
achievement, in motor development: lifting their heads while lying on their stomachs. After lifting the
head, infants progress through an orderly series of motor milestones: lifting the chest, reaching for
objects, rolling over, and sitting up with support (Table 4.2).
Notice that these motor achievements reflect a cephalocaudal progression of motor control, proceeding
from the head downward (see Chapter 3) (Payne & Isaacs, 2020). Researchers have long believed that all
motor control proceeds from the head downward, but we now know that motor development is more
variable. Instead, some infants may sit up before they roll over or not crawl at all before they walk
(Adolph & Robinson, 2015). Similarly, infants reach for toys with their feet weeks before they use their
hands, suggesting that early leg movements can be precisely controlled, the development of skilled
reaching need not involve lengthy practice, and early motor behavior does not necessarily follow a strict
cephalocaudal pattern (Galloway & Thelen, 2004).
Milestone charts describe group trends in motor development, which do not always predict the behavior
of individuals. That is, depictions of orderly successions of skills by age can be deceiving because
individual infants’ development often diverges from group norms (Adolph et al., 2018). Although
crawling is presumed to precede walking, some infants skip crawling altogether or crawl after walking
(Adolph & Robinson, 2015).
Table 4.2 Motor Skills Timetable
Average Age Achieved Motor Skill
2 months
Lifts head
Holds head steady when held upright
3 months
Pushes head and chest up with arms
Rolls from stomach to back
4 months
6 months
7 months
Grasps cube
Sits without support
Rolls from back to stomach
Attempts crawling
Uses opposable thumb to grasp objects
8 months
Achieves sitting position alone
Pulls to a stand
9 months
10 months
11 months
12 months
“Cruises” by holding on to furniture
Plays patty-cake
Stands alone
Walks alone
Average Age Achieved Motor Skill
14 months
Builds tower of two cubes
Scribbles
17 months
18 months
Walks up steps
Runs
Success at initiating forward motion, crawling (6–10 months), is particularly significant for both infants
and parents. Infants vary in how they crawl (Adolph & Robinson, 2015). Some use their arms to pull and
legs to push, some use only their arms or only their legs, and others scoot on their bottoms. Once
infants can pull themselves upright while holding on to a chair or table, they begin “cruising,” moving by
holding on to furniture to maintain their balance while stepping sideways. In many Western
industrialized countries, most infants walk alone by about 1 year of age.
Once babies can walk, their entire visual field changes. Whereas crawling babies are more likely to look
at the floor as they move, walking babies gaze straight ahead at caregivers, walls, and toys (Kretch et al.,
2014). Most beginning walkers, even through 19 months of age, tend to walk in shorts spurts, a few
steps at a time, often ending in the middle of the floor (Cole et al., 2016). Independent walking holds
implications for cognitive, social, and emotional development, as it is associated not only with more
attention and manipulation of objects but also with more sophisticated social interactions with
caregivers, such as directing mothers’ attention to particular objects and sharing objects (Veldman et al.,
2019; Yamamoto et al., 2020; ). These behaviors, in turn, are associated with advanced language
development relative to nonwalkers in both U.S. and Chinese infants (Ghassabian et al., 2016; He et al.,
2015).
By the end of the first month of life, most infants can lift their head while
lying on their stomach.
iStock/aywan88
Fine Motor Development
Fine motor development refers to the ability to control small movements of the fingers such as
reaching and grasping. Voluntary reaching plays an important role in cognitive development because it
provides new opportunities for interacting with the world. Like other motor skills, reaching and grasping
prereaching
begin as gross activity and are refined with time. Newborns begin by engaging in
, swinging
their arms and extending them toward nearby objects (Ennouri & Bloch, 1996; von Hofsten & Rönnqvist,
1993). Newborns use both arms equally and cannot control their arms and hands, so they rarely succeed
in making contact with objects of interest (Lynch et al., 2008). Prereaching stops at about 7 weeks of age.
Voluntary reaching appears at about 3 months of age and slowly improves in accuracy. Infants reach for
and bump objects and eventually some are accidentally grasped (Juett & Kuipers, 2019). At 5 months,
infants can successfully reach for moving objects. By 7 months, the arms can reach independently, and
infants are able to reach for an object with one arm rather than both (Spencer et al., 2000). By 10
months, infants can reach for moving objects that change direction (Fagard et al., 2009).
As they gain experience with reaching and acquiring objects, infants develop cognitively because they
learn by exploring and playing with objects—and object preferences change with experience. In one
study, 4- to 6-month-old infants with less reaching experience spent more time looking at and exploring
larger objects, whereas 5- to 6-month-old infants with more reaching experience spent more time
looking at and touching smaller objects. The older infants did this despite first looking at and touching
the largest object (Libertus et al., 2013). With experience, infants’ attention moves away from the motor
skill (like the ability to coordinate their movement to hit a mobile), to the object (the mobile), as well as
to the events that occur before and after acquiring the object (how the mobile swings and how grabbing
it stops the swinging or how batting at it makes it swing faster). In this way, infants learn about cause
and how to solve simple problems.
Biological and Contextual Determinants of Motor Development
Motor development illustrates the complex interactions that take place between maturation and
contextual factors.
Biological Influences on Motor Development
Motor development is influenced by genetics. Identical twins, who share the same genes, have more
similarities in the timing and pace of motor development than do fraternal twins, who share half of their
genes (Smith et al., 2017). However, the differences are small.
Maturation plays a very strong role in motor development. Preterm infants reach motor milestones later
than do full-term infants (Gabriel et al., 2009). Cross-cultural research also supports the role of
maturation because around the world, infants display roughly the same sequence of motor milestones.
Among some Native Americans and other ethnic groups around the world, it is common to follow the
tradition of tightly swaddling infants to cradleboards and strapping the board to the mother’s back
during nearly all waking hours for the first 6 to 12 months of the child’s life. Although this might lead
one to expect that swaddled babies will not learn to walk as early as babies whose movements are
unrestricted, studies of Hopi Native American infants have shown that swaddling has little impact on
when Hopi infants initiate walking (Dennis & Dennis, 1991; Harriman & Lukosius, 1982). Such research
suggests that walking is very much maturationally programmed. Samples of young children in the
United States show no ethnic or socioeconomic status differences in gross motor skills such as running,
hopping, kicking, and catching (Kit et al., 2017).
Contextual Influences on Motor Development
Much of motor development is driven by maturation, yet opportunities to practice motor skills are also
important. In a classic naturalistic study of institutionalized orphans in Iran who had spent their first 2
years of life lying on their backs in their cribs and were never placed in sitting positions or played with,
none of the 1- to 2-year-old infants could walk, and fewer than half of them could sit up; the researchers
also found that most of the 3- to 4-year-olds could not walk well alone (Dennis, 1960). Recent research
suggests that infants raised in orphanages score lower on measures of gross motor milestones at 4, 6,
and 8 months of age and walk later compared with home-reared infants (Chaibal et al., 2016). While
maturation is necessary for motor development, it is not sufficient; we must also have opportunities to
practice our motor skills.
In fact, practice can enhance motor development (Lobo & Galloway, 2012). Newborns show
improvement in stepping after practicing on a treadmill (Siekerman et al., 2015). When infants from 1 to
7 weeks of age practice stepping reflexes each day, they retain the movements and walk earlier than
infants who receive no practice (Vereijken & Thelen, 1997; Zelazo, 1983). Practice in sitting has a similar
effect (Zelazo et al., 1993). Even 1-month-old infants given postural training showed more advanced
control of their heads and necks than other infants (Lee & Galloway, 2012). Similarly, infants who spend
supervised playtime prone on their stomachs each day reach many motor milestones, including rolling
over and crawling, earlier than do infants who spend little time on their stomachs (Hewitt et al., 2020;
Kuo et al., 2008).
In one study over a 2-week period, young infants received daily play experience with “sticky mittens”—
Velcro-covered mitts that enabled them to independently pick up objects. These infants showed
advances in their reaching behavior and greater visual exploration of objects, while a comparison group
of young infants who passively watched an adult’s actions on the objects showed no change (Libertus &
Needham, 2010). Sticky mittens training in reaching at 3 months of age predicts object exploration at 15
months of age, and training also predicts social perception, consistent with the lifespan principle that
domains of development, such as motor and cognitive development, interact (Libertus et al., 2016; van
den Berg & Gredeback, 2020).
Practice contributes to cross-cultural differences in infant motor development. Different cultures provide
infants with different experiences and opportunities for development. In many cultures, including several
in sub-Saharan Africa and in the West Indies, infants attain motor goals like sitting up and walking much
earlier than do North American infants. Among the Kipsigi of Kenya, parents seat babies in holes dug in
the ground and use rolled blankets to keep babies upright in the sitting position (Keller, 2003). The
Kipsigis help their babies practice walking at 2 to 3 months of age by holding their hands, putting them
on the floor, and moving them slowly forward. Notably, Kipsigi mothers do not encourage their infants
to crawl; crawling is seen as dangerous as it exposes the child to dirt, insects, and the dangers of fire pits
and roaming animals. Crawling is therefore virtually nonexistent in Kipsigi infants (Super & Harkness,
2015).
Infants of many sub-Saharan villages, such as the !Kung San, Gusii, and Wolof, are also trained to sit
using holes or containers for support and are often held upright and bounced up and down, a social
interaction practice that contributes to earlier walking (Lohaus et al., 2011). Caregivers in some of these
cultures further encourage walking by setting up two parallel bamboo poles that infants can hold onto
with both hands, learning balance and stepping skills (Keller, 2003). Similarly, mothers in Jamaica and
other parts of the West Indies use a formal handling routine to exercise their babies’ muscles and help
them to grow up strong and healthy (Dziewolska & Cautilli, 2006; Hopkins, 1991; Hopkins & Westra,
1989, 1990).
Infants’ motor development varies with cultural styles of interaction, such as a Western cultural emphasis
on individualism and Eastern cultural emphasis on collectivism. In one cross-cultural study comparing
infants in Germany and in the Cambodian Nso culture, the Nso infants showed overall more rapid motor
development. The Nso practice of close proximity, lots of close body contact, and less object play are
related to the socialization goals of fostering relationships; they also provide infants with body
stimulation that fosters gross motor skills. German mothers displayed a parenting style with less body
contact but more face-to-face contact and object play, socialization practices that emphasize
psychological autonomy but less gross motor exploration. However, the German infants learned how to
roll from back to stomach earlier than the Nso infants, likely because Nso infants are rarely placed on
their backs and instead are carried throughout the day (Lohaus et al., 2011).
Although practice can speed development and caregivers in many cultures provide their infants with
opportunities for early practice of motor skills, sometimes survival and success require continued
dependence on caregivers and delaying motor milestones. Crawling may not be encouraged in
potentially dangerous environments, such as those with many insects, rodents, and/or reptiles on the
ground. The nomadic Ache of eastern Paraguay discourage their infants from crawling or moving
independently. Ache infants walk at 18 to 20 months, compared with the 12-month average of North
American infants (Kaplan & Dove, 1987).
Although this infant spends most of his waking hours tightly swaddled and
carried on his mother’s back, he will walk at about a year of age, similar to
babies who are not swaddled.
Norman Barrett/Alamy Stock Photo
Even simple aspects of the childrearing context, such as choice of clothing, can influence motor
development. In the 19th century, 40% of American infants skipped crawling, possibly because the long,
flowing gowns they wore impeded movement on hands and knees (Trettien, 1990). One study of 13- and
19-month-old infants compared their gait while wearing a disposable diaper, a thicker cloth diaper, and
no diaper (Cole et al., 2012). When naked, infants demonstrated the most sophisticated walking with
fewer missteps and falls. While wearing a diaper, infants walked as poorly as they would have done
several weeks earlier had they been walking naked. In sum, motor development is largely maturational,
but subtle differences in context and cultural emphasis play a role in its timing.
Motor milestones, such as the ability to crawl, might look like isolated achievements, but they actually
develop systematically and build on each other with each new skill preparing an infant to tackle the next
(Thelen, 1995, 2000). Infants’ first steps, may seem like a sudden new ability, but it is similar to other
unnoticed motor behaviors that are the result of continuously combining and experimenting with many
existing skills (Adolph et al., 2018). Every motor behavior, such as walking, has a long history and is not a
stand-alone achievement. According to dynamic systems theory, (see Chapter 1), motor development
reflects an interaction among developmental domains, maturation, and environment (Thelen, 1995,
2000) (Figure 4.17). Simple motor skills are combined in increasingly complex ways, permitting advances
in movement, including a wider range and more precise movements that enable babies to more
effectively explore and control their environments.
Description
Figure 4.17 Motor Development as a Dynamic System
Source: iStock/Essentials Collection; iStock/Essentials Collection; Can Stock
Photo Inc./harishmarnad
Separate abilities are blended together to provide more complex and effective ways of exploring and
controlling the environment. The abilities to sit upright, hold the head upright, match motor movements
to vision, reach out an arm, and grasp are all combined into coordinated reaching movements to obtain
a desired object (Corbetta & Snapp-Childs, 2009; Spencer et al., 2000). Motor skills become more
specialized, coordinated, and precise with practice, permitting infants to reach for an object with one
hand without needlessly flailing the other (D’Souza et al., 2017).
Motor skills also reflect the interaction of multiple domains of development. All movement relies on the
coordination of our senses and cognitive abilities to plan and predict actions. Sensory abilities such as
binocular vision and the ability to direct gaze combine with exploratory hand and foot movements,
designed to determine the opportunities a given surface provides for movement. When 14-month-old
infants were tested on a “bridge” of varying widths, they explored the bridge first with quick glances
(Kretch & Adolph, 2017). When faced with an impossibly narrow width, infants with walking experience
tended to engage in more extensive and time-consuming perceptual and motor exploration, such as
touching with hands and feet, to determine whether to cross it.
Motor development reflects goal-oriented behavior because it is initiated by the infant's or child’s desire
to accomplish something, such as picking up a toy or moving to the other side of the room. Infants’
abilities and their immediate environments (e.g., whether they are being held, lying in a crib, or lying
freely on the floor) determine whether and how the goal can be achieved (Spencer et al., 2000). The
infant tries out behaviors and persists at those that enable him or her to move closer to the goal,
practicing and refining the behavior. Infants learn to walk by taking many steps and making many falls,
but they persist even though, at the time, crawling is a much faster and more efficient means of
transportation (Adolph et al., 2012). Why? Perhaps because upright posture leads to many more
interesting sights, objects, and interactions. The upright infant can see more and do more, with two
hands free to grasp objects, making walking a very desirable goal (Adolph & Tamis-LeMonda, 2014).
New motor skills provide new possibilities for exploring the environment and new interactions with
caregivers that influence opportunities. Differences in caregiver interactions and caregiving
environments affect children’s motor skills, the form they take, the ages of onset, and the overall
developmental trend (Adolph & Franchak, 2017).
Social and cultural influences provide context to our movements. Motor skills do not develop in
isolation; rather, they are influenced by the physical and social context in which they occur. A naturalistic
study of video records of at-home interactions of mother–infant pairs from six countries revealed large
differences in opportunities for infant sitting and infant performance (Karasik et al., 2015). Infants from
the United States, Argentina, South Korea, and Italy spent most of their sitting time in places that offered
postural support, such as child furniture.
In contrast, infants from Kenya and Cameroon, who spent most of their sitting time in places that
offered little postural support, such as the ground or adult furniture, tended to show the longest bouts
of independent sitting and at the earliest age. Cultural differences in daily activities influence motor skills
across the lifespan. Long-distance running is part of daily life for Tarahumaran people, who routinely run
10 to 40 kilometers in a few hours as children, and as adults run 150 to 300 kilometers in 24 to 48 hours
(Adolph & Franchak, 2017). From childhood, East African females carry heavy loads balanced on their
heads, altering their posture and gait to complete a contextually important activity.
Therefore, from a dynamic systems perspective, motor development is the result of several processes:
central nervous system maturation, the infant’s physical capacities, environmental supports, and the
infant’s desire to explore the world. It is learned by revising and combining abilities and skills to fit the
infant’s goals. In this way, motor development is highly individualized as each infant has goals and
opportunities that are particular to his or her specific environment (Adolph & Franchak, 2017). An infant
might respond to slippery hardwood floors by crawling on her stomach rather than all fours or by
shuffling her feet and hands rather than raising each. Infants attain the same motor tasks, such as
climbing down stairs, at about the same age, yet differ in how they approach the task. Some might turn
around and back down, others descend on their bottoms, and others slide down face first (Berger et al.,
2007). By viewing motor development as dynamic systems of action produced by an infant’s abilities,
goal-directed behavior, and environmental supports and opportunities, we can account for the individual
differences that we see in motor development.
Thinking in Context: Lifespan Development
1. From a bioecological systems perspective, describe contextual influences on motor development.
How do factors in an infant’s microsystem and exosystem influence their motor skills? How might
exosystem factors play a distal, or distant, influence on motor skills? Identify macrosystem cultural
factors that might influence an infant’s development.
2. How might a fine motor skill, such as learning to use a spoon, reflect the interaction of maturation
and sociocultural context?
Thinking in Context: Applied Developmental Science
Carmen is concerned because her 14-month-old baby is not walking. All of the other babies she knows
have walked by 12 months of age. What would you tell Carmen?
APPLY YOUR KNOWLEDGE
Lena is 7 months old and lags behind in height and weight as compared with other infants her age. Early
in life, she showed normative growth, but her growth has since slowed. Recently, Lena’s parents
separated, and she and her mother moved to a new home. Her mother is 19 years old, does not have a
high school degree, and had few job opportunities. She took the first job that panned out, despite its
long hours. Lena was placed in child care. Her mother continued to breastfeed, despite its increasing
difficulty given her new work schedule. Lena’s mother insisted that Lena eat less solid food and baby
food, given her continued breastfeeding. Staff at the child care center approached Lena’s mother to
express their concern over Lena’s lack of growth and development; she has not begun crawling like
other infants and tends to avoid eye contact with others.
1. What are patterns of normative growth for infants? What are influences on growth, and how might
they explain Lena’s development?
2. How do motor skills unfold during infancy? When do you think Lena’s caregivers should worry
about her?
3. What are potential causes of or influences on the developmental difficulties Lena experiences? How
might contextual factors influence Lena’s development?
4. What are the child care staff’s responsibilities?
5. What should the mother do? What treatment do you suggest?
CHAPTER SUMMARY
4.1
Discuss patterns of growth and influences on growth during infancy and toddlerhood.
Growth proceeds from the head downward (cephalocaudal) and from the center of the body
outward (proximodistal). Breastfeeding is associated with many benefits for mothers and infants.
Socioeconomic and racial differences in breastfeeding rates are influenced by the experience of
barriers, such as lack of knowledge, poor support, and workplace restrictions. At about 6 months
infants begin to eat solid foods.
4.2
Examine threats to infant and toddler health.
Malnourishment is associated with growth stunting and impaired learning, concentration, and
language skills throughout childhood and adolescence. Severely malnourished children may suffer
from diseases such as marasmus and kwashiorkor or, more common in the United States, growth
faltering. Other threats to infants’ health include SIDS and under-immunization.
4.3
Summarize processes of brain development and the influence of experience on brain
development during infancy and toddlerhood.
The brain develops through several processes: neurogenesis (the creation of neurons),
synaptogenesis (the creation of synapses), pruning (reducing unused neural connections), and
myelination (coating the axons with myelin to increase the speed of transmission). Experience
shapes the brain structure through pruning. Sleep also plays a role in brain development. Although
infancy is a particularly important time for the formation and strengthening of synapses, experience
shapes the brain structure at all ages of life.
4.4
Compare infants’ early learning capacities for habituation, classical conditioning, operant
conditioning, and imitation.
Innate learning capacities permit young infants to quickly adapt to the world. Habituation is a type
of innate learning in which repeated exposure to a stimulus results in the gradual decline in the
intensity, frequency, or duration of a response. In classical conditioning, an association is formed
between a neutral stimulus and one that triggers an innate reaction. Infants also learn based on the
consequences of the behaviors, whether they are followed by reinforcement or punishment, known
as operant conditioning. Neonates mimic simple facial and finger expressions but do so without
control. The regulatory mechanisms to inhibit imitative responding develop during infancy.
4.5
Describe infants’ developing sensory abilities.
Visual acuity, pattern perception, visual tracking, and color vision improve over the first few months
of life. Neonates are sensitive to depth cues and young infants can distinguish depth, but crawling
stimulates the perception of depth and the association of fear with sharp drops. Newborns can
perceive and discriminate nearly all sounds in human languages, but from birth they prefer to hear
their native language. Intermodal perception is evident at birth as infants can combine information
from more than one sensory system.
4.6
Contrast maturation, contextual, and dynamic systems explanations for motor development in
infancy and toddlerhood.
Infants are born with reflexes, each with its own developmental course. Gross and fine motor skills
develop systematically and build on each other, with each new skill preparing the infant to tackle
the next. Much of motor development is influenced by maturation, but infants benefit from
contextual factors such as opportunities to practice motor skills. Different cultures provide infants
with different experiences and opportunities for practice, contributing to cross-cultural differences
in motor development. Viewing motor development as dynamic systems of action produced by an
infant’s abilities, goal-directed behavior, and environmental supports and opportunities accounts for
the individual differences that we see in motor development.
Key Terms
Affordances
Cephalocaudal development
Classical conditioning
Corpus callosum
Cortex
Depth perception
Dishabituation
Experience-dependent brain development
Experience-expectant brain development
Externality effect
Fine motor development
Glial cells
Gross motor development
Growth faltering
Growth norms
Growth stunting
Habituation
Infant circumcision
Intermodal perception
Kwashiorkor
Lateralization
Marasmus
Myelin
Myelination
Neurogenesis
Neurons
Perception
Perceptual narrowing
Prefrontal cortex
Proximodistal development
Reflex
Sensation
Sensitive periods
Sudden infant death syndrome (SIDS)
Synapses
Synaptic pruning
Synaptogenesis
Vaccine
Visual acuity
Descriptions of Images and Figures
Back to Figure
The x-axis of the graph shows different types of origin in 2017. The y-axis on the left is labeled Infant
deaths per 1, 000 live births from 0 to 12 in increments of 2. The data are as follows:
Race and Hispanic Origin
White
Black
American Indian or Alaska Native
Asian
Native Hawaiian or Other Pacific
Islamnder
Hispanic
Back to Figure
Mortality rate
Postneonatal mortality
rate
1.63
3.82
4.41
1.08
3.82
Neonatal mortality
rate
3.40
7.16
4.77
2.71
3.82
1.54
3.56
Total
4.67
10.97
9.21
3.78
7.64
5.10
The x-axis represents the percent of households and the y-axis represents the household composition
and race/ethnicity of head. The approximate data are as follows:
Household composition
Percent of households
With children <18
16
With children <6
17
Married couples with children 9
Single women with children
30
Single men with children
19
Other households with child 18
Back to Figure
Race/ethnicity of head
Percent of households
White non-Hispanic 8
Black non-Hispanic 22
Hispanic
18
Other non-Hispanic 10
The horizontal axis shows the years 1990 through 2015, in increments of 5. The vertical axis shows the
deaths per 100,000 live births from 0 to 180, in increments of 20. The approximate data are as follows:
Year
Combined SUID Sudden infant death
Unknown
rate
syndrome
cause
Deaths per 100,000 Live Births
1990 155
130
20
1995 100
85
20
2000 95
60
30
2005 98
55
30
2010 85
50
20
2015 90
35
30
Back to Figure
Accidental suffocation and
strangulation in bed
3
3
8
12
15
20
The figure is divided into two parts. From top to bottom, they are labeled a and b. The details of the
parts are as follows.
Part a: It includes six images in a row. From left to right, they are Newborn, 1, 3, 6, 15 and 24 months old.
The complexity of neurons is found to increase quickly after birth and is found to peak at 24 months.
Part b: It includes six images in a row. From left to right, they are New, 1 month, 2.5 month, 15-16 month,
2.5 years and 28-30 years. The complexity of apical dendrites peaks at 2.5 years.
Back to Figure
The lobes include: frontal lobe at the front; parietal lobe in the middle; occipital lobe at the back; and
temporal lobe at the sides of the brain. Also depicted are lines, marking the central sulcus and lateral
fissure between frontal lobe and parietal lobe and frontal lobe and temporal lobe respectively.
Back to Figure
The horizontal axis shows the number of trials, in increments of 5. The vertical axis shows the looking
time. The line for the habituation start from the top left and decline for the first trial, raise for the second
trial and then decline for the next three trials. After the trial six, it split into two sub lines named as
continued habituation and dishabituation. There is a dot line passes through the initial points of the
continued habituation and dishabituation. The name of the line is change pattern.
Back to Figure
From left to right, the upper photos of the man are with tongue protruded, open mouth, and an
annoyed expression. The bottom photos of the newborn baby have exactly the same expressions as that
of the adult just above it.
Back to Figure
A rectangular box divided vertically into two halves. The details of the boxes are as follows.
Left half: It includes two similar stars, the star at the left has shading at one of the corners made by a 1month-old infant while the star at the right has shading almost all over the surface made by a 2-monthold infant.
Right half: It includes at the left, the face of a female, which bears marking along the hairline
representing a 1-month-old infant’s gaze and at the right, the face of a male with markings on the eyes,
and mouth representing a 2-month-old infant’s gaze.
Back to Figure
Multiple lines graph depicting the rates of circumcision performed from year 1979 to 2010. The
horizontal axis represents years 1979, 1985, 1990, 1995, 2000, 2005 and 2010 and the vertical axis
represents percent of male newborn infants ranges from 0 to 85 in increments of 5. The approximate
data are as follows:
Year
Midwest Northeast
South
West
Percent of male newborn infants
1979 74
66
56
64
1985 71
65
56
49
1990 76
63
57
43
1995 82
67
66
43
2000 83
65
63
37
2005 80
66
58
32
2010 71
66
58
41
Back to Figure
From top to bottom the details of the photographs are as follows:
At the top is a newborn baby lying on a crib with raised hands trying to reach out to the toy
hangings above the crib.
In the middle is an infant lying on his stomach on the floor trying to reach out to a ball in front of
him.
At the bottom is a toddler running in front with a ball in his hands and behind him are his parents
with smiling faces walking fast to reach with him.
A left curly bracket covers the three photos and points toward the text “Behavior.” On the upper left side
of the photographs is the text “Maturation (biological, cognitive and psychosocial),” on the upper right
side is the text “Contextual (supports and challenges),” and below the bottom photograph is the text
“Goals and understanding.” There are curved double headed arrows between the texts.
5 COGNITIVE DEVELOPMENT IN INFANCY AND
TODDLERHOOD
Blend Images—JGI/Jamie Grill/Getty Images
David eagerly crawled toward the open cupboard. Just as he began to peer inside, his father bent and
swooped David into his arms, “That’s not for you, David. Let’s find something for you to play with.” Soon
David sat amidst several toys: a set of stacking rings, cups and bowls, and a giant telephone with wheels
and a string. “Overdoing it?” asked David’s mother. “Just giving David options,” his father explained.
“Everyone wants a choice, right?” Soon David placed several stacking rings in a bowl, and then tried to
balance the bowl on the giant telephone. “See? David’s figuring it all out in his own, unorthodox, way.”
David’s father grasps an important principle: individuals actively contribute to their own development, as
noted in Chapter 1. We learn by acting on the world and making sense of our observations. In this
chapter we examine how infants interact with the world around them to influence their cognitive
development.
PIAGET’S COGNITIVE-DEVELOPMENTAL THEORY: SENSORIMOTOR
REASONING
LEARNING OBJECTIVE
5.1 Discuss the cognitive-developmental perspective on infant reasoning.
Swiss scholar Jean Piaget (1896–1980) was the first scientist to systematically examine children’s
thinking. Piaget viewed infants and children as active explorers who learn by interacting with the world,
building their own understanding of everyday phenomena, and applying it to adapt to the world around
them.
Processes of Development
According to Piaget (1952), infants and children are active in their own development because they
engage other people and the world, adapting their ways of thinking in response to their experiences.
Through these interactions, individuals organize what they learn to construct and refine their own
cognitive schemas, or concepts, ideas, and ways of interacting with the world. The earliest schemas are
inborn motor responses, such as the reflex response that causes infants to close their fingers around an
object when it touches their palm. As infants grow and develop, these early motor schemas are
transformed into schemas, or thoughts and ideas. At every age, we rely on our schemas to make sense
of the world, and our schemas are constantly adapting and developing in response to our experiences.
Piaget also emphasized the importance of two developmental processes that enable us to cognitively
adapt to our world: assimilation and accommodation.
Assimilation involves integrating a new experience into a preexisting schema. Suppose that 1-year-old
Makayla uses the schema of “grab and shove into the mouth” to learn. She grabs and shoves her rattle
into her mouth, learning about the rattle by using her preexisting schema. When Makayla comes across
another object, such as Mommy’s keys, she transfers the schema to it—and assimilates the keys by
grabbing them and shoving them into her mouth. Makayla develops an understanding of the new
objects through assimilation, by fitting them into her preexisting schema.
Sometimes we encounter experiences or information that do not fit within an existing schema, so we
must change the schema, adapting and modifying it in light of the new information. This process is
called accommodation. Suppose Makayla encounters another object, a beach ball. She tries her schema
of grab and shove, but the beach ball won’t fit into her mouth; perhaps she cannot even grab it. She
must adapt her schema or create a new one in order to incorporate the new information—to learn about
the beach ball. Makayla may squeeze and mouth the ball instead, accommodating or changing her
schema to interact with the new object.
The processes of assimilation and accommodation enable people to adapt to their environment,
absorbing the constant flux of information they encounter daily (Figure 5.1). People—infants, children,
and adults—constantly integrate new information into their schemas and continually encounter new
information that requires them to modify their schemas. Piaget proposed that people naturally strive for
cognitive equilibrium, a balance between the processes of assimilation and accommodation. When
assimilation and accommodation are balanced, individuals are neither incorporating new information
into their schemas nor changing their schemas in light of new information; instead, our schemas match
the outside world and represent it clearly. But a state of cognitive equilibrium is rare and fleeting. More
frequently, people experience a mismatch, or cognitive disequilibrium, between their schemas and the
world.
Disequilibrium leads to cognitive growth because the mismatch between schemas and reality leads to
confusion and discomfort, which in turn motivate children to modify their schemas so that their view of
the world matches reality. It is through assimilation and accommodation that this modification takes
place so that cognitive equilibrium is restored. Children’s drive for cognitive equilibrium is the basis for
cognitive change, propelling them through the four stages of cognitive development proposed by
Piaget (refer back to Chapter 1). With each advancing stage, children create and use more sophisticated
schemas, enabling them to think, reason, and understand their world in more complex ways.
Description
Figure 5.1 Assimilation and Accommodation
Source: iStock/GlobalP; iStock/YouraPechkin
Sensorimotor Substages
“There you go, little guy,” Mateo’s uncle says, placing a rattle within the infant’s grasp. Six-month-old
Mateo shakes the toy and puts it in his mouth, sucking on it. He then removes the rattle from his mouth
and gives it a vigorous shake, dropping it to the ground. “Mateo! Where’s your rattle?” asks his mother.
“Whenever he drops his toy, he never looks for it,” she explains to Mateos uncle, “not even when it’s his
favorite toy.” Mateo displays sensorimotor thinking. During the sensorimotor stage, from birth to about
2 years old, infants learn about the world through their senses and motor skills. To think about an object,
they must act on it by viewing it, listening to it, touching it, smelling it, and tasting it. Piaget (1952)
believed that infants are not capable of mental representation—thinking about an object using mental
pictures. They also lack the ability to remember and think about objects and events when they are not
present. Instead, in order to think about an object, an infant must experience it through both the visual
and tactile senses. The sensorimotor period of reasoning, as Piaget conceived of it, progresses through
six substages in which cognition develops from reflexes to intentional action to symbolic representation.
At each stage infants are driven to learn and explore the world.
Substage 1: Reflexes (Birth to 1 Month)
In the first substage, newborns use their reflexes, such as the sucking and palmar grasp reflexes, to react
to stimuli. During the first month of life, infants use these reflexes to learn about their world through the
process of assimilation; they apply their sucking schema to assimilate information and learn about their
environment. At about 1 month of age, newborns begin to accommodate, or modify, their sucking
behaviors to specific objects, sucking differently in response to a bottle versus a pacifier. They may
modify their sucking schema when they encounter a pacifier, perhaps sucking less vigorously and
without swallowing. During the first month of life, newborns strengthen and modify their original
reflexive schemas to explore the world around them.
In the first substage (birth to 1 month), newborns use their reflexes to
respond to stimuli. They strengthen and modify their reflexive schemas to
explore the world around them.
iStock/Stefano Oppo
Substage 2: Primary Circular Reactions (1 to 4 Months)
During the second substage, infants begin to make accidental discoveries. Early cognitive growth in the
sensorimotor period comes through engaging in circular reaction, the repetition of an action and its
response. Infants learn to repeat pleasurable or interesting events that originally occurred by chance.
Between 1 and 4 months, infants engage in behaviors called primary circular reactions, which consist of
repeating actions involving parts of the body that produce pleasurable or interesting results. A primary
circular reaction begins by chance, as infants produce an interesting and pleasurable sensation and learn
to repeat the behaviors to make the event happen again and experience the interesting and pleasurable
effect again. While flailing her little arms, baby Lucia accidentally puts her hand in her mouth. She is
surprised and delighted at the outcome (her hand in her mouth) and tries to make it happen again.
Therefore, Lucia repeats the behavior to experience and explore her body, a primary circular reaction.
In the second substage (1 to 4 months), infants discover that they can control
their bodies and repeat the behavior to experience and explore their bodies.
iStock/W6
Substage 3: Secondary Circular Reactions (4 to 8 Months)
During the third sensorimotor substage, as infants’ awareness extends further, they engage in secondary
circular reactions, repetitions of actions that trigger responses in the external environment. Now the
patterns of repetition are oriented toward making interesting events occur in the infant’s environment.
Baby Aria shakes a rattle to hear its noise and kicks her legs to move a mobile hanging over the crib. Aria
demonstrates secondary circular reactions. Aria’s attention has expanded to include the environment
outside her body and she is beginning to understand that her actions cause results in the external world.
In this way, infants discover new ways of interacting with their environments to continue experiencing
sensations and events that they find pleasing.
During the third sensorimotor substage (4 to 8 months), infants’ awareness
extends to include objects. They repeat actions to view and experience their
effects on objects.
iStock/Wavebreakmedia
Substage 4: Coordination of Secondary Circular Reactions (8 to 12 Months)
Unlike primary and secondary circular reactions, behaviors that are discovered by accident, the
coordination of secondary circular reactions substage represents true means–end behavior and signifies
the beginning of intentional behavior. During this substage, infants purposefully coordinate two
secondary circular reactions and apply them in new situations to achieve a goal. Piaget described how
his son, Laurent, combined the two activities of knocking a barrier out of his way and grasping an object.
When Piaget put a pillow in front of a matchbox that Laurent desired, the boy pushed the pillow aside
and grabbed the box. In this way, Laurent integrated two secondary circular reactions to achieve a goal.
Now, planning and goal-directed behavior have emerged.
One of the most important advances during the coordination of secondary circular reactions stage is
object permanence, the understanding that objects continue to exist outside of sensory awareness (e.g.,
when they are no longer visible). According to Piaget, infants younger than 8 months of age do not yet
have object permanence—out of sight is literally out of mind. An infant loses interest and stops reaching
for or looking at a small toy after it is covered by a cloth. Not until 8 to 12 months, during the
coordination of secondary circular reactions stage, will an infant search for hidden objects, thus
displaying object permanence. This development is an important cognitive advance because it signifies a
capacity for mental representation, or internal thought. The ability to think about an object internally is
an important step toward learning language because language uses symbols: Sounds symbolize and
stand for objects (e.g., infants must understand that the sound “ball” represents an object, a ball).
During the fourth substage (8 to 12 months), infants demonstrate object
permanence, the understanding that objects exist outside of sensory
awareness.
Doug Goodman/Science Source
Substage 5: Tertiary Circular Reactions (12 to 18 Months)
During the fifth substage, infants begin to experiment with new behaviors to see the results. Piaget
described infants as “little scientists” during this period because they move from intentional behavior to
systematic exploration. In what Piaget referred to as tertiary circular reactions, infants now engage in
mini-experiments: active, purposeful, trial-and-error exploration to search for new discoveries (Figure
5.2).
Description
Figure 5.2 Primary, Secondary, and Tertiary Circular Reactions
They vary their actions to see how the changes affect the outcomes. Many infants begin to experiment
with gravity by dropping objects to the floor while sitting in a highchair. First an infant throws a ball and
watches it bounce. Next a piece of paper floats slowly down. Then Mommy’s keys clatter to the floor.
And so on. This purposeful exploration is how infants search for new discoveries and learn about the
world. When presented with a problem, infants in the tertiary circular reactions substage engage in trialand-error analyses, trying out behaviors until they find the best one to attain their goal.
During the fifth substage (12 to 18 months), infants begin to experiment with
new behaviors to see the results.
iStock/Kyryl Gorlov
Substage 6: Mental Representation (18 to 24 Months)
The sixth sensorimotor substage marks a transition between the sensorimotor and preoperational
reasoning stages. Between 18 and 24 months of age, infants develop representational thought—the
ability to use symbols such as words and mental pictures to represent objects and actions in memory. In
developing this ability, infants are freed from immediate experience: They can think about objects that
they no longer see directly in front of them and can engage in deferred imitation, imitating actions of an
absent model. Now, external physical exploration of the world gives way to internal mental exploration.
Children can think through potential solutions and create new solutions without engaging in physical
trial and error but simply by considering the potential solutions and their consequences. Table 5.1
summarizes the substages of sensorimotor reasoning.
Table 5.1 Substages of Sensorimotor Reasoning
Substage
Reflexive
activity (0–1
month)
Primary
circular
reactions (1–4
months)
Secondary
circular
reactions (4–8
months)
Coordination
of secondary
schemas (8–
12 months)
Major Features
Strengthens and adapts
reflexes
Repeats motor actions that
produce interesting outcomes
that are centered toward the
body
Repeats motor actions that
produce interesting outcomes
that are directed toward the
environment
Combines secondary circular
reactions to achieve goals and
solve problems; the
beginnings of intentional
behavior
Tertiary
Experiments with different
circular
actions to achieve the same
reactions (12– goal or observe the outcome
18 months)
and make new discoveries
Mental
Internal mental
representation representation of objects and
(18–24
events; thinking to solve
months)
problems rather than relying
on trial and error
Example
Newborn shows a different sucking response to a
nipple versus a pacifier.
Infant bats mobile with arm and watches arm move.
Infant bats mobile with arm and watches the mobile
move.
Infant uses one hand to lift a bucket covering a ball
and the other to grasp the ball. Infant uses both
hands to pull a string attached to a ball and eventually
reach the ball.
Toddler hits a pot with a wooden spoon and listens to
the sound, then hits other objects in the kitchen, such
as the refrigerator, stove, or plates, to hear the sound
that the spoon makes against those objects.
When confronted with a problem, like a toy that is out
of reach on the counter, toddlers consider possible
solutions to a problem in their mind, decide on a
solution, and implement it.
Thinking in Context: Applied Developmental Science
Identify a toy appropriate for an infant in the secondary circular reactions substage (e.g., a loud rattle or
jingling set of toy keys).
1. Compare and contrast how infants in the secondary circular reactions substage and coordination
of secondary schemas substage might play with the toy.
2. How might infants in the tertiary reactions substage play with it?
3. How might infants’ play match their developing schemes?
4. Might parent–infant interactions, the home environment, and sociocultural context influence
when infants develop object permanence? Why or why not?
EVALUATING SENSORIMOTOR REASONING
LEARNING OBJECTIVE
5.2 Evaluate Piaget’s sensorimotor reasoning stage in light of research evidence.
Without a doubt, Piaget’s contributions to understanding cognitive development are invaluable. Piaget
was the first scientist to examine infants’ and children’s thinking and ask what develops during
childhood and how it occurs. Piaget recognized that motor action and cognition are inextricably linked,
a view still accepted by today’s developmental scientists (Adolph & Hoch, 2019; Oakes & Rakison, 2020).
Criticism of the sensorimotor reasoning stage tends to center around the method Piaget used to assess
infants’ abilities. Newer methods have yielded different results.
Methods for Studying Object Permanence
Measuring the cognitive capabilities of infants and toddlers is very challenging because, unlike older
children and adults, infants cannot fill out questionnaires or answer questions orally. Researchers have
had to devise methods of measuring observable behavior that can provide clues to what an infant is
thinking. Researchers measure infants’ looking behavior by determining what infants look at and for how
long. Using such methods, they have found support for some of Piaget’s claims and evidence that
challenges others. One of the most contested aspects of Piaget’s theory concerns his assumption that
infants are not capable of mental representation until late in the sensorimotor period (Carey et al., 2015;
Crain, 2016). A growing body of research conducted with object permanence and imitation tasks
suggests otherwise, as described in the following sections.
Violation-of-Expectation Tasks
Piaget’s method of determining an infant’s understanding of object permanence relied on the infant’s
ability to demonstrate it by uncovering a hidden object. Researchers have posted that many infants may
understand that the object is hidden but lack the motor ability to coordinate their hands to physically
demonstrate their understanding. Studying infants’ looking behavior enables researchers to study object
permanence in younger infants with undeveloped motor skills because it eliminates the need for infants
to use motor activity to demonstrate their cognitive competence.
One such research design uses a violation-of-expectation task, a task in which a stimulus appears to
violate physical laws (Hespos & Baillargeon, 2008). Specifically, in a violation-of-expectation task, an
infant is shown two events: one that is labeled
because it follows physical laws and a second
that is called
(or “impossible”) because it violates or is incongruous with physical laws
(Mireault & Reddy, 2020). If the infant looks longer at the unexpected event, it suggests that he or she is
surprised by it, is aware of physical properties of objects, and can mentally represent them.
unexpected
expected
In a classic study, developmental researcher Renée Baillargeon (1987) used the violation-of-expectation
method to study the mental representation capacities of very young infants. Infants were shown a
drawbridge that rotated 180 degrees. Then the infants watched as a box was placed behind the
drawbridge to impede its movement. Infants watched as either the drawbridge rotated and stopped
upon hitting the box (expected event) or did not stop and appeared to move through the box (an
“impossible” event). As shown in Figure 5.3, 4½-month-old infants looked longer when the drawbridge
appeared to move through the box (the unexpected “impossible” event) than when it stopped upon
hitting the box, as expected. Baillargeon and colleagues interpreted infants’ behavior as suggesting that
the infants maintained a mental representation of the box, even though they could not see it, and
therefore understood that the drawbridge could not move through the entire box.
Description
Figure 5.3 Object Permanence in Young Infants: Baillargeon’s Drawbridge
Study
Source: Turk-Browne et al. (2008).
Critics argue that these results do not demonstrate object permanence but rather illustrate infants’
preference for novelty or for greater movement (Bogartz et al., 2000; Heyes, 2014). When the study was
replicated without the box, 5-month-old infants looked longer at the full rotation, suggesting that
infants looked at the unexpected event not because it violated physical laws but because it represented
greater movement (Rivera et al., 1999).
Recently pupillometry has been proposed as an alternative to looking-time measures of infant attention
(Krüger et al., 2019; Zhang & Emberson, 2020). The pupil is a small opening in the eye that dilates,
becomes larger, in response to changes in light and also in response to novel or surprising stimuli
(Alamia et al., 2019). Two recent studies employing pupillometry in violation of expectations tasks
suggest that 10-month-old infants’ pupillary responses indicate perceptual preferences for stimuli rather
than object permanence (Pätzold & Liszkowski, 2020; Sirois & Jackson, 2012). These conclusions are
puzzling because Piaget’s original tasks demonstrated object permanence at 9 months.
Although the violation-of-expectation method is widely used to study infant cognition, its validity is also
debated (Rubio-Fernández, 2019). Nevertheless, when considering the question of whether infants
display object permanence, studies that use simpler tasks have shown support for young infants’
competence. Four- and 5-month-old infants will watch a ball roll behind a barrier, gazing to where they
expect it to reappear (von Hofsten et al., 2007). When 6-month-old infants are shown an object and the
lights are then turned off, they will reach in the dark for the object (Shinskey, 2012), suggesting that they
maintain a mental representation of the object and therefore have object permanence earlier than
Piaget believed.
A-Not-B Tasks
Other critics of Piaget’s views of infants’ capacity for object permanence focus on an error that 8- to 12month-old infants make, known as the A-not-B error. The A-not-B error involves the following scenario:
An infant repeatedly uncovers a toy hidden behind a barrier. He then sees the toy moved from behind
one barrier (Place A) to another (Place B), but he continues to look for the toy in Place A, even after
watching it be moved to Place B (Figure 5.4). Piaget believed that the infant incorrectly, but persistently,
searches for the object in Place A because he lacks object permanence.
Description
Figure 5.4 A-Not-B Error
Some researchers point out that infants look at Place B, the correct location, at the same time as they
mistakenly reach for Place A, suggesting that they understand the correct location of the object (Place B)
but cannot keep themselves from reaching for Place A because of neural and motor immaturity
(Diamond, 1991). Other researchers propose that infants cannot restrain the impulse to repeat a
behavior that was previously rewarded (Zelazo et al., 1998).
When looking-time procedures are used to study the A-not-B error (Ahmed & Ruffman, 1998), infants
look longer when the impossible event occurs (when the toy is moved from Place A to Place B but is
then found at Place A) than when the expected event occurs (when the toy is moved from Place A to
Place B and is found at Place B). This suggests that infants have object permanence, but their motor skills
prohibit them from demonstrating it in A-not-B tasks. One longitudinal study followed infants from 5 to
10 months of age and found that between 5 and 8 months, infants showed better performance on an Anot-B looking task than on a reaching task. Nine- and 10-month-old infants performed equally well on
A-not-B looking and reaching tasks (Cuevas & Bell, 2010). Age-related changes in performance on Anot-B and other object permanence tasks may be due to maturation of brain circuitry controlling motor
skills and inhibition as well as advances in the ability to control attention (Cuevas & Bell, 2010;
Marcovitch et al., 2016).
Deferred Imitation Tasks
Another method of studying infants’ capacities for mental representation relies on deferred imitation,
the ability to repeat an act performed some time ago. Piaget (1962) believed that infants under 18
months cannot engage in deferred imitation because they lack mental representation abilities. Yet
laboratory research on infant facial imitation has found that 6-week-old infants who watch an unfamiliar
adult’s facial expression will imitate it when they see the same adult the next day (Meltzoff & Moore,
1994). Six- and 9-month-old infants also display deferred imitation of unique actions performed with
toys, such as taking a puppet’s glove off, shaking it to ring a bell inside, and replacing it over a 24-hour
delay (Barr et al., 2003).
When infants engage in deferred imitation, they act on the basis of stored representations of actions—
memories—a contradiction of Piaget’s beliefs about infants’ capabilities (Jones & Herbert, 2006). Many
researchers now suggest that deferred imitation, along with object permanence itself, is better viewed as
a continuously developing ability rather than the stage-like shift in representational capacities that
Piaget proposed (Miller, 2016). A 3-year longitudinal study of infants 12, 18, and 24 months old showed
that performance on deferred imitation tasks improved throughout the second year of life (Kolling et al.,
2010). Between 12 and 18 months, infants remember modeled behaviors for several months and imitate
peers as well as adults (Hayne et al., 2000). They also imitate across contexts, imitating behaviors that
they learn in child care at home (Patel et al., 2013).
Increases in imitative capacity are observed with development up to 30 months of age. In addition,
imitative capacity increases when shorter sequences of action are used, such as a sequence of fewer than
eight unique actions (Kolling et al., 2010; Kressley-Mba et al., 2005). Furthermore, research following
infants from 9 to 14 months of age suggests that individual differences in imitation are stable; children
who show lower levels of imitation at 9 months of age continue to score lower on imitation at 14
months (Heimann & Meltzoff, 1996). These gradual changes suggest that infants and toddlers increase
their representational capacities in a continuous developmental progression.
Core Knowledge Theory
Developmental psychologists generally agree with Piaget’s description of infants as eagerly interacting
with the world, actively taking in information, and constructing their own thinking. However, many
researchers no longer agree with Piaget’s belief that all mental abilities arise from sensorimotor activity.
Instead, infants are thought to have some innate, or inborn, cognitive capacities. Some theorists believe
that infants are born with limited learning capacities such as a set of perceptual biases that cause them
to attend to features of the environment that will help them to learn quickly (Bremner et al., 2015). Other
developmental scientists support core knowledge theory, the view that infants are born with several
innate knowledge systems, or core domains of thought, that promote early rapid learning and
adaptation (Spelke, 2016).
According to core knowledge theorists, infants learn so quickly and encounter such a great amount of
sensory information that some prewired evolutionary understanding, including the early ability to learn
rules, must be at work (Spelke, 2017). Using the violation-of-expectation method, core knowledge
researchers have found that young infants have a grasp of the physical properties of objects, including
the knowledge that objects do not disappear out of existence (permanence), cannot pass through
another object (solidity), and will fall without support (gravity) (Baillargeon et al., 2016). Infants also
display early knowledge that liquids are nonsolid substances able to pass through grids (Hespos et al.,
2016).
Infants are also thought to have early knowledge of numbers (Cheung & Ansari, 2020; Spelke, 2017).
Five-month-old infants can discriminate between small and large numbers of items (Christodoulou et al.,
2017). Even newborns are sensitive to large differences in number, distinguishing nine items from three,
but newborns show difficulty distinguishing small numbers from each other (two vs. three items)
(Coubart et al., 2014; Di Giorgio et al., 2019). Comparative research has shown that animals display these
systems of knowledge early in life and without much experience (Piantadosi & Cantlon, 2017),
suggesting that it is possible—and perhaps evolutionarily adaptive—for infants to quickly yet naturally
construct an understanding of the world (Bjorklund, 2018).
Much core knowledge research employs the same looking paradigms described earlier, in which infants’
visual preferences are measured as indicators of what they know, and this approach has come under
criticism. Critics argue that it is unclear whether we can interpret looking in the same way in infants as in
adults. Such measures demonstrate discrimination—that young infants can tell the difference between
stimuli—yet perceiving the difference between two stimuli does not necessarily mean that infants
understand how the two stimuli differ (Bremner et al., 2015). Others have suggested that infants are not
detecting differences in number but rather differences in area (Mix et al., 2002). It may be that the infant
differentiates nine items from three not because of the change in number but simply because nine items
take up more space than three. More recent research has shown that 7-month-old infants can
differentiate changes in number and area, are more sensitive to changes in number than area, and prefer
to look at number changes than area changes (Libertus et al., 2014).
Infants’ sophisticated abilities are thought to rely on an inborn ability to recognize patterns. Increasingly,
infants are viewed as statistical learners, able to apply basic inferences to quickly identify patterns in the
world around them (Denison & Xu, 2019; Köster et al., 2020; Saffran & Kirkham, 2018). When those
statistical inferences do not match their perception, they show “surprise,” as indicated by longer looking
time (Sim & Xu, 2019). Moreover, the “surprise” (increased looking) infants show when their expectation
is violated may drive infants to learn and retain information as they are naturally motivated to create and
test new hypotheses about the world around them (Stahl & Feigenson, 2019). It is important to note that
this is not a conscious process; infants do not know that they are experimenting and engaging in the
scientific method. Instead, infants are driven to learn. When confronted with confusing events, they
spontaneously devise explanations and compare those explanations with what they perceive (Köster et
al., 2020).
Overall, Piaget’s theory has had a profound influence on how we view cognitive development. But
infants and toddlers are more cognitively competent than Piaget imagined, showing signs of
g
y
p
g
g
,
g g
representational ability and conceptual thought that he believed were not possible. Developmental
scientists agree with Piaget that immature forms of cognition give way to more mature forms, that the
individual is active in development, and that interaction with the environment is critical for cognitive
growth.
Thinking in Context: Applied Developmental Science
1. Consider the range of object permanence tasks discussed. What are the advantages and
disadvantages of each?
2. Different kinds of experimental tasks measuring object permanence often yield different results.
Explain. What do you conclude about infants’ abilities?
Thinking in Context: Lifespan Development
1. Can you make a case for contextual factors as an influence on object permanence? Might object
permanence unfold differently based on context? Explain your perspective, with examples.
2. To what extent would core knowledge theorists agree with your assessment?
INFORMATION PROCESSING THEORY
LEARNING OBJECTIVE
5.3 Describe the information processing system and its development in infancy.
Information processing theorists describe cognition as a set of interrelated components that permit
people to process information—to notice, take in, manipulate, store, and retrieve. Newborns are ready
to learn and adapt to their world because they are born information processors. In the following sections
we examine the information processing system and how cognition changes in infancy.
Information Processing System
According to information processing theory, the mind is composed of three mental stores: sensory
memory, working memory, and long-term memory (Atkinson & Shiffrin, 1968). All throughout our lives,
information moves through these three stores, and we use them to manipulate and store information
(Figure 5.5).
Description
Figure 5.5 Information Processing System
Sensory memory is the first step in getting information into the mind; it holds incoming sensory
information in its original form (Vandenbroucke et al., 2014). Look at this page, then close your eyes. Did
you “see” the page for a fraction of a second after you closed your eyes? That image, or icon, represents
your sensory memory. Information fades from sensory memory quickly if it is not processed. Visual
information decays in about a quarter of a second and auditory information lasts about 4 seconds
(Radvansky, 2017).
A great deal of information is taken in and rapidly moves through sensory memory. Not surprisingly,
much of it is discarded. When we direct our attention, or awareness, toward information, it passes to the
next part of the information processing system, working memory (Oberauer, 2019). Working memory
holds and processes information that is being “worked on” in some way. Working memory consists of at
least three components: a short-term store, a processing component, and a control mechanism
(Baddeley et al., 2019). Just as your thoughts are constantly changing, so are the contents of working
memory. We can hold only so much information in working memory (perhaps as many as 9 and as few
as 4 or 5), and we can hold it for a short period, from seconds to minutes (Radvansky, 2017). Indeed, a
core assumption of the information processing approach is the idea of limited capacity (Bjorklund &
Myers, 2015; Oberauer et al., 2016).
Working memory is responsible for manipulating (considering, comprehending), encoding (transforming
into a memory), and retrieving (recalling) information. All of your thoughts—that is, all conscious mental
activities—occur within working memory. Reading this paragraph, remembering assignments, and
considering how this material applies to your own experience taps your working memory.
An important part of working memory is the central executive, a control mechanism or processor that
directs the flow of information and regulates cognitive activities such as attention, action, and problemsolving (Baddeley et al., 2020; Vandierendonck, 2016). The central executive determines what is
important to attend to, combines new information with information already in working memory, and
selects and applies strategies for manipulating the information in order to understand it, make decisions,
and solve problems (Baddeley, 2012). Collectively, these cognitive activities are known as executive
function.
As information is manipulated in working memory, it becomes more likely that it will enter long-term
memory, the third mental store. Long-term memory is an unlimited store that holds information
indefinitely. Information is not manipulated or processed in long-term memory; it is simply stored until it
is retrieved to manipulate in working memory (e.g., in remembering events and thinking about them).
Although developed with adults, research has shown that infants, children, and adolescents have the
same memory stores and the structure of the information processing system remains the same
throughout the lifespan (Baddeley et al., 2020; Siegler, 2016). We are born with the ability to take in,
store, and manipulate information through our sensory, working, and long-term memory. With
development, we get better at moving information through our cognitive system in ways that allow us
to adapt to our world. Processing speed, the speed with which we can complete a mental task, increases
rapidly in early infancy, from 3 months of age (Saint et al., 2017). We can process more information,
retain more information, and do so more quickly and efficiently.
Attention
Attention refers to our ability to direct our awareness. The ability to focus and switch attention is critical
for selecting information to process in working memory and is influenced by neurological development,
including advances in myelination (Reynolds & Romano, 2016b). Important developments in attention
occur over the course of infancy and continue throughout childhood.
Infant attention is often studied using the same methods used to learn about their visual perception
(Chapter 4). Preferential-looking procedures (measuring and comparing the length of time infants look
at two stimuli) and habituation procedures (measuring the length of time it takes infants to show a
reduction in how long they look at a nonchanging stimulus) are used to study infants’ attention to visual
stimuli, such as geometric patterns (Ristic & Enns, 2015). Infants show more attentiveness to dynamic
stimuli—stimuli that change over time—than to static, unchanging stimuli (Reynolds et al., 2013).
By around 10 weeks of age, infants show gains in attention. As infants’ capacities for attention increase,
so do their preferences for complex stimuli. In one experiment, 3- to 13-month-old infants were shown
displays that included a range of static and moving stimuli (Courage et al., 2006). From about 6½
months of age, infants’ looking time varied with stimulus complexity, decreasing for simple stimuli such
as dot patterns, increasing slightly for complex stimuli such as faces, and increasing more for very
complex stimuli such as video clips (Courage et al., 2006). Overall, looking time peaked at 14 weeks of
age and dropped steadily, demonstrating infants’ growing cognitive efficiency. As infants become more
g
pp
y,
g
g
g g
y
efficient at directing their attention to scan and process visual information, they require less exposure to
stimuli to habituate.
Studies that measure infant heart rate have identified changes in heart rate that coincide with phases of
attention (Reynolds & Romano, 2016a). Heart rate rises as infants notice and attend to a stimulus,
signifying interest. Heart rate falls then plateaus with sustained attention, as infants focus on the
stimulus over time. When infants stop attending, the heart rate declines to prestimulus levels. Infants
actively attend to stimuli they find interesting, and their interest motivates their exploration.
Attention is linked with development in the brain areas underlying attentional control (Dowe et al.,
2020). In response to tasks that challenge attention, infants show widespread activity in the prefrontal
cortex (responsible for thinking and planning) at 5.5 months of age but more specific or localized by 7.5
months of age (Richards, 2010). Attention is vital to thought and plays a role in memory and learning
(Fisher, 2019).
The toy keys have captured this infant’s attention. Infants are most attentive
to dynamic stimuli—stimuli that change over time—than to static,
unchanging stimuli.
iStock/kamsta
Memory
We have memory capacities at birth. Newborn infants display sensory memory, but it is much shorter in
duration than adults’ memory (Cheour et al., 2002). Given that infants are unable to speak and tell us
what they are thinking, it is difficult to assess memory.
Working Memory
Working memory is thought to improve alongside development of the prefrontal cortex. Infants’
working memory is assessed by observing reaching and looking behaviors. The duration of working
memory can be assessed with delayed response tasks in which an object is shown to an infant and is
then hidden among several boxes; the infant is allowed to search for the object after a short (such as a
10-second) delay (Simmering, 2016). Delayed response tasks can be used as soon as infants are able to
reliably reach for items, at about 5–6 months of age.
Recent research has employed a new, non-motor, visual indicator of working memory: pupil size (Kaldy
& Blaser, 2020). As discussed earlier in this chapter, the pupil dilates, or gets larger, in response to
interesting stimuli. In one study, 7-month-olds but not 4-month-olds showed larger pupil dilation to
previously seen items compared with novel ones, suggesting that the 7-month-olds, but not the 4month-olds, recalled the stimuli (Hellmer et al., 2018). The durability of memory increases rapidly from 6
to 12 months, with continued increases through age 2 (Reznick, 2009).
Similar techniques are used to study the capacity of working memory, the number of items an infant can
recall. The capacity of working memory dramatically increases between 6 months of age, when infants
can reliably recall a single item, to 12–14 months, when infants can reliably recall three objects, similar to
some adults (Kibbe, 2015; Oakes & Luck, 2013). Does this mean that infants have similar memory
abilities as adults? Just as attention advances throughout infancy, childhood, and adolescence, so does
working memory. Although infants may recall objects, they likely do not process stimuli in the same way
as adults. In a recent looking-time study, 6- month-old infants demonstrated recall of an object in a
hidden place but could not remember the distinct features of the object (Kibbe & Leslie, 2019). That is,
they could recall that an object was hidden, but not
object, a ball or a human-like doll head,
suggesting that infants’ memory, while impressive, is still developing.
which
Long-Term Memory
Recognition memory, the ability to recognize a previously encountered stimulus, appears early in life.
Habituation studies measuring looking time and brain activity demonstrate that neonates can recall
visual and auditory stimuli (Muenssinger et al., 2013; Streri et al., 2013). With age, infants require fewer
trials or presentations to recall a stimulus and are able to retain material for progressively longer periods
of time (Cuevas & Sheya, 2019; Howe, 2015). Infants can also remember motor activities. In one study, 2to 3-month-old infants were taught to kick their foot, which was tied to a mobile with a ribbon, to make
the mobile move. One week later, when the infants were reattached to the mobile, they kicked
vigorously, indicating their memory of the first occasion. The infants would kick even 4 weeks later if the
experimenter gave the mobile a shake to remind them of its movement (Rovee-Collier & Bhatt, 1993).
Infants’ long-term memory, the ability to recall information encountered some time in the past, has been
assessed with tasks that measure deferred imitation, imitating a model after a delay. The infant watches
an experimenter engage in a novel behavior with an unfamiliar object. After a period of time, the infants
are given the object. If they display the novel behavior more often than infants who have not viewed the
object, it suggests that they have formed a long-term memory for the object and action. Results from
deferred imitation studies suggest that infants can form memories that last a year and sometimes longer
(Bauer et al., 2000, 2002).
With age, infants can remember more complicated sets of actions, with fewer exposures, and for a
longer period of time (Cuevas & Sheya, 2019). Nine-month-old infants shown a two-step sequence of
actions (such as hanging a plate from a bar and striking it with a mallet) can imitate the action after a 1month delay if they viewed the event at least three times, but not if it was viewed less than three times.
Thirteen-, 16-, and 20-month-old infants can imitate a more complicated three-step sequence of actions
over a longer delay, with older infants showing higher levels of deferred imitation than younger infants
(Bauer et al., 2000) (Figure 5.6).
Description
Figure 5.6 Recall in Infancy and Toddlerhood
Source: Bauer (2002).
Infants’ memory is influenced by contextual factors (Cuevas & Sheya, 2019). They are most likely to
remember events that take place in familiar contexts and in which they are actively and emotionally
engaged (Courage & Cowan, 2009; Rose et al., 2011). One method for testing the effect of emotional
engagement on memory is the still-face interaction paradigm. In this experimental task, an infant
interacts with an adult who first engages in normal social interaction and then suddenly lets his or her
face become still and expressionless, not responsive to the infant’s actions (Tronick et al., 1978). Infants
usually respond to the adult’s still face with brief smiles followed by negative facial expressions, crying,
looking away, thumb sucking, and other indications of emotional distress (Shapiro et al., 1998; Weinberg
& Tronick, 1994). In one study, 5-month-old infants who were exposed to the still face demonstrated
recall over a year later, at 20 months of age, by looking less at the woman who had appeared in the
earlier still-face paradigm than at two other women whom the infants had never previously seen
(Bornstein, Arterberry, et al., 2004). Generally, with age, infants create memories more quickly and retain
them for longer periods, but at all ages infants are more likely to recall events that take place in familiar
surroundings in which they are actively engaged and that are emotionally salient (Courage & Cowan,
2009; Learmonth et al., 2004). As we develop, we amass a great deal of information in long-term
memory, organize it in increasingly sophisticated ways, and encode and retrieve it more efficiently and
with less effort.
Young infants were taught to kick their foot to make an attached mobile
move. When tested one week later, the infants remembered and kicked their
legs vigorously to make the mobile move.
iStock/Vera Livchak
Infants’ Thinking
In infants’ eyes, all of the world is new—“one great blooming, buzzing confusion,” in the famous words
of 19th-century psychologist William James (1890). How do infants think about and make sense of the
world? As infants are bombarded with a multitude of stimuli, encountering countless new objects,
people, and events, they form concepts by naturally grouping stimuli into classes or categories.
Categorization, grouping different stimuli into a common class, is an adaptive mental process that
allows for organized storage of information in memory, efficient retrieval of that information, and the
capacity to respond with familiarity to new stimuli from a common class (Owen & Barnes, 2019; Quinn,
2016). Infants naturally categorize information, just as older children and adults do (Rosenberg &
Feigenson, 2013). Without the ability to categorize, we would have to respond anew to each novel
stimulus we experience.
Just as in studying perception and attention, developmental researchers must rely on basic learning
capacities, such as habituation, to study how infants categorize objects (Rigney & Wang, 2015). For
example, infants are shown a series of stimuli belonging to one category (e.g., fruit: apples and oranges)
and then are presented with a new stimulus of the same category (e.g., a pear or a lemon) and a
stimulus of a different category (e.g., a cat or a horse). If an infant dishabituates or shows renewed
interest by looking longer at the new stimulus (e.g., cat), it suggests that he or she perceives it as
belonging to a different category from that of the previously encountered stimuli (Cohen & Cashon,
2006). Using this method, researchers have learned that 3-month-old infants categorize pictures of dogs
and cats differently based on perceived differences in facial features (Quinn et al., 1993).
Infants’ earliest categories are based on the perceived similarity of objects (Rakison & Butterworth,
1998). By 4 months, infants can form categories based on perceptual properties, grouping objects that
are similar in appearance, including shape, size, and color (Quinn, 2016; Rekow et al., 2020). As early as 7
months of age, infants use conceptual categories based on perceived function and behavior (Mandler,
2004). Moreover, patterns in 6- to 7-month-old infants’ brain waves correspond to their identification of
novel and familiar categories (Quinn et al., 2010). Seven- to 12-month-old infants use many categories
to organize objects, such as food, furniture, birds, animals, vehicles, kitchen utensils, and more, based on
both perceptual similarity and perceived function and behavior (Bornstein & Arterberry, 2010; Mandler &
McDonough, 1998; Oakes, 2010).
Researchers also use sequential touching tasks to study the conceptual categories that older infants
create (Perry, 2015). Infants are presented with a collection of objects from two categories (e.g., four
animals and four vehicles) and their patterns of touching are recorded. If the infants recognize a
categorical distinction among the objects, they touch those from within a category in succession more
than would be expected by chance. Research using sequential touching procedures has shown that 12to 30-month-old toddlers organize objects first at a global level and then at more specific levels. They
categorize at more inclusive levels (e.g., animals or vehicles) before less inclusive levels (e.g., types of
animals or types of vehicles) and before even less inclusive levels (e.g., specific animals or vehicles)
(Bornstein & Arterberry, 2010). Infants’ and toddlers’ everyday experiences and exploration contribute to
their growing capacity to recognize commonalities among objects, group them in meaningful ways, and
use these concepts to think and solve problems. Recognizing categories is a way of organizing
information that allows for more efficient thinking, including storage and retrieval of information in
memory (Owen & Barnes, 2019). Therefore, advances in categorization are critical to cognitive
development. The cognitive abilities that underlie categorization also influence language development
as words represent categories, ways of organizing ideas and things.
As shown in Table 5.2, information processing capacities, such as attention, memory, and categorization
skill, show continuous change over the first 3 years of life (Rose et al., 2009). Infants get better at
attending to the world around them, remembering what they encounter, and organizing and making
sense of what they learn. Infants’ emerging cognitive capacities influence all aspects of their
development and functioning, including intelligence. Cognitive development is also influenced by the
contexts in which infants and children live.
Table 5.2 Changes in Information Processing Skills During Infancy
Ability
Description
Ability
Attention
Description
Attention increases steadily over infancy.
From birth, infants attend more to dynamic than static stimuli.
During the second half of their first year, infants attend more to complex stimuli such
as faces and video clips.
Attention is linked with diffuse frontal lobe activity in young infants and localized
frontal lobe activity by 7½ months of age.
Individual differences appear at all ages and are stable over time.
Attention is associated with performance on visual recognition memory tasks.
Memory
Memory improves with age.
Three-month-old infants can remember a visual stimulus for 24 hours.
By the end of the first year, infants can remember a visual stimulus for several days or
even weeks.
Infants are most likely to remember events in familiar, engaging, and emotionally
salient contexts.
Categorization
Infants first categorize objects based on perceived similarity.
By 4 months, infants can form categories based on perceptual properties such as
shape, size, and color.
By 6 to 7 months of age, infants’ brain waves correspond to their identification of
novel and familiar categories.
Seven- to 12-month-old infants can organize objects such as food, furniture, animals,
and kitchen utensils, based on perceived function and behavior.
Twelve- to 30-month-old infants categorize objects first at a global level and then at
more specific levels.
Infants categorize objects at more global and inclusive levels (such as motor vehicles)
before more specific and less inclusive levels (such as cars, trucks, construction
equipment).
The use of categories improves memory efficiency.
Culture and Cognitive Development
Theories of infant cognition tend to emphasize infants’ construction of new ways of thinking through
interactions with the world (such as Piaget) and development of information processing capacities, such
as advances in attention and memory. A criticism of cognitive-developmental and information
processing approaches is that they give little attention to the role of context in cognitive development.
The social and cultural contexts in which infants are embedded provide opportunities for social
interactions that affect how infants think and view their world (Veissière et al., 2019). Through social play
with infants, caregivers convey relevant information about the nature of objects and people (Deák et al.,
2014; Wu et al., 2011).
Children’s social learning opportunities are facilitated and constrained by culture (Kärtner et al., 2020;
Legare et al., 2015). Research with Western samples suggests that caregivers promote children’s learning
through shared attention, by directing their attention to objects by using clear visual cues such as
pointing and alternating their gaze between the infant and object. However, emphasis on instruction,
stimulation, and engagement with infants during object play is more common in Western cultures, such
as Germany and Greece, than non-Western cultures, such as rural Cameroon and rural India (Keller et al.,
2009). Many non-Wwestern communities, such as the !Kung, Gusii, and Samoan communities,
emphasize physical contact with infants instead of the visual, face-to-face contact common in Western
communities (Konner, 2017).
In many communities, learning may occur through observation without direct adult instruction or cues
(Gaskins & Paradise, 2010; Kärtner et al., 2020). Children who grow up in cultural communities where
observational learning is valued, such as in agricultural communities where children learn to participate
in household tasks at an early age, tend to become skilled observational learners, even as infants, which
influences how they process stimuli in their world. In one study, 14- to 20-month-old Guatemalan Mayan
and middle-class U.S. children were exposed to co-occurring events, such as being given a new toy to
explore while other events were happening in the room. U.S. children tended to focus on only one event
at a time whereas the Mayan children tended to simultaneously monitor multiple events by rapidly
shifting their attention from one to other or by manipulating the toy while observing the other events
(Chavajay & Rogoff, 1999). Attending to events in this way fosters learning from observation by
permitting children the opportunity to learn from interactions that do not involve them.
Caregivers of different cultures interact with infants and objects in different ways. One recent study
compared caregiver–child interactions among Western parents from the United States and those on the
island of Tanna in Vanuatu, an isolated agricultural country in which children learn from a very young
age to be responsible for assisting adults in cooking, planting and harvesting crops, prepping for
ceremonial gatherings, and helping with the child care of younger siblings (Little et al., 2016). Vanuatu
children learn through observing and participating in daily activities (Rogoff, 2003; Rogoff, Mistry, Göncü,
& Mosier, 1993). When mothers were observed interacting with their infant with a novel object, both U.S.
and Vanuatu mothers engaged in similar amounts of interactions with the infant and object, but the type
varied. Vanuatu caregivers spent more time physically engaging infants with the object compared with
U.S. caregivers, who used visual cues such as eye gaze to direct the infants. Although infants learn from
their social world, the means by which they learn appears to vary by cultural context.
New Contexts for Learning: Screens and Digital Media
We are immersed in an online context that influences our thoughts, actions, and development. The
American Academy of Pediatrics advises that parents avoid screen time other than video chatting for
children younger than 18 to 24 months (American Academy of Pediatrics Council on Communications
and Media, 2016). Exposure to screen media is associated with increased risk of obesity, reduced sleep
and poor sleep, language delays, and poor performance on tests of inhibition—the ability to stop
responding to a stimulus (Anderson & Subrahmanyam, 2017; Cheung et al., 2017; DominguesMontanari, 2017). Today, media is so pervasive that it is no longer simply an influence on infants’ and
children’s development but a fundamental context in which development unfolds (Barr, 2019). Infants
and toddlers spend 1 to 2 hours a day engaged with screen media, including television and tablets, and
are exposed to over 5 hours daily of background television intended for adults (Courage, 2017).
Infant-directed videos and programming, which offer educational content embedded in an engaging
video format, are often advertised as aids to babies’ brain development, intelligence, and learning
(Fenstermacher et al., 2010; Vaala & LaPierre, 2014). Most parents believe that age-appropriate videos
can have a positive impact on early child development while providing good entertainment for babies
and convenience for parents (Robb et al., 2009). Certainly, even very young infants attend to video
material, as its movement, color, and rapid scene changes are attractive (Courage, 2017).
But do baby videos really aid development? Brain-building claims made by baby media manufacturers
are not supported by longitudinal studies, which offer no evidence of long-term benefits of media use in
early childhood (American Academy of Pediatrics Council on Communications and Media, 2016; Courage
& Howe, 2010; Ferguson & Donnellan, 2014). One study tested a popular DVD program that claims to
help young infants learn to read. Ten- to 18-month-old infants who regularly watched the program for 7
months did not differ from other infants in intelligence, cognitive skills, reading skill, or word knowledge
(Neuman et al., 2014). Baby videos are often advertised as aiding language development, yet several
studies found that children under 2 years of age showed no learning of target words after viewing a
language-learning DVD up to 20 times (DeLoache et al., 2010; Ferguson & Donnellan, 2014).
Infants learn more readily from people than from televisions and tablets. After watching a best-selling
DVD that labels household objects, 12- to 18-month-old infants learned very little from it compared with
infants learning through similar interactions with parents (DeLoache et al., 2010). Infants experience a
transfer deficit, sometimes called the video deficit, because they are less able to transfer what they see
on the screen to their own behavior than what they learn through active interactions with adults (Barr,
2010). The transfer deficit applies to a variety of domains, such as imitation, language learning, and
object retrieval tasks (Barr, 2013; Strouse & Samson, 2020). In conditions of joint media engagement,
such as when parents watch videos along with their infants and talk to them about the content, the
infants spend more time looking at the screen and learn more from the media (Barr, 2019; Padilla‐
Walker et al., 2020).
Infants and toddlers learn more from interaction with their parents and other
caregivers than they do watching infant-directed educational content.
iStock/LucaLorenzelli
The transfer deficit is influenced by the noncontingent nature of most media. Infants learn from
contingent interactions with others. Infants can also learn from screens when contingent interactions
with people are involved (McClure et al., 2018). For example, 12- to 25-month-olds were presented with
on-screen partners who taught novel words, actions, and patterns via real-time FaceTime conversations
or prerecorded videos (Myers et al., 2017). All of the infants were attentive and responsive, but only
children in the FaceTime group responded to the partner in a time-synchronized manner. One week
later, the children in the FaceTime group preferred and recognized their partner, learned more novel
patterns, and (among the older infants) learned more novel words. Infants can learn from screen
interactions, but they learn better from in-person partners than video chat partners (Myers et al., 2019).
Infants are immersed in a digital world and are faced with a new developmental task of learning to
navigate this world, including learning from digital screen media. The video deficit declines over early
childhood, but infants and young children benefit most from engaging with sensitive caregivers over
screens of any kind.
Thinking in Context: Lifespan Development
1. Recall from Chapter 1 that developmental scientists vary in whether they view development as
continuous, gradual, or as discontinuous, stage-like. Consider cognition in infancy. To what degree
do you view it as continuous or discontinuous. Why?
2. Examine cognitive development from a bioecological perspective. How do macrosystem factors,
such as culture and society; exosystem factors, such as community; and microsystem factors, such as
home and child care, influence cognitive development?
Thinking in Context: Applied Developmental Science
1. What kinds of toys and activities would you recommend to caregivers who want to entertain
infants while helping them develop skills in attention, memory, or categorization?
2. Marla sat her 12-month-old infant to watch a program on a tablet computer. “I need a break—
and it’s educational,” she reasoned. What do you think? What are the pros and cons of infant screen
use? What advice would you give? Is it ever OK? Why or why not?
INDIVIDUAL DIFFERENCES IN COGNITIVE ABILITIES
LEARNING OBJECTIVE
5.4 Discuss individual differences in infant intelligence.
As we have discussed, infants are born with cognitive abilities that develop rapidly. Infants vary in their
set of mental skills. Most simply put, intelligence refers to an individual’s ability to adapt to the world.
Different people have different levels of intelligence—an example of the concept of individual
differences or variation from one individual to another (see Chapter 1). Intelligence tests are used to
measure these differences; they include questions that measure memory, pattern recognition, verbal
knowledge, quantitative abilities, and logical reasoning. Measuring intelligence in infancy is challenging
because, as noted earlier, infants cannot answer questions. Instead, researchers who study infant
intelligence rely on an assortment of nonverbal tasks—the same kinds of methods that are used to study
cognitive development. There are two general approaches to studying intelligence in infancy. As
discussed next, the testing approach emphasizes standardized tests that compare infants with agebased norms. A second approach, the information processing approach, examines specific processing
skills.
Testing Infant Intelligence
At 3 months of age, Baby Lourdes can lift and support her upper body with her arms when on her
stomach. She grabs and shakes toys with her hands and enjoys playing with other people. Lourdes’s
pediatrician tells her parents that her development is right on track for babies her age and that she
shows typical levels of infant intelligence. Standardized tests permit the pediatrician to determine
Lourdes’s development relative to other infants her age.
The most often used standardized measure of infant intelligence is the Bayley Scales of Infant
Development III (BSID-III), commonly called “Bayley-III.” This test is appropriate for infants from 1 month
through 42 months of age (Bayley, 1969, 2005). The Bayley-III consists of five scales: three consisting of
infant responses and two of parent responses. The
measures gross and fine motor skills,
such as grasping objects, drinking from a cup, sitting, and climbing stairs. The
includes
items such as attending to a stimulus or searching for a hidden toy. The
examines
comprehension and production of language, such as following directions and naming objects. The
is derived from parental reports regarding behavior such as the infant’s
responsiveness and play activity. Finally, the
is based on parental reports of the
infant’s ability to adapt in everyday situations, including the infant’s ability to communicate, regulate his
or her emotions, and display certain behavior.
Motor Scale
Social-Emotional Scale
Adaptive Behavior Scale
Cognitive Scale
Language Scale
Infant assessment tests, such as the BSID-III, examine cognitive, language,
social-emotional, and motor abilities, such as infants’ skill in manipulating
objects.
Cliff Moore/Science Source
The Bayley-III provides a comprehensive profile of an infant’s current functioning, but the performance
of infants often varies considerably from one testing session to another (Bornstein et al., 1997). Scores
vary with infants’ states of arousal and motivation. This suggests that pediatricians and parents must
exert great care in interpreting scores—particularly poor scores—because an infant’s performance may
be influenced by factors other than developmental functioning. Infants who perform poorly on the
Bayley-III should be reexamined.
Although Bayley-III scores offer a comprehensive profile of an infant’s abilities, scores do not predict
performance on tests of intelligence and executive function in childhood (Gould et al., 2019; Luttikhuizen
dos Santos et al., 2013; Månsson et al., 2019). Even Nancy Bayley, who invented the Bayley Scales, noted
in a longitudinal study (1949) that infant performance was not related to intelligence scores at age 18.
Why is infant intelligence relatively unrelated to later intelligence? Consider what is measured by infant
tests: perception and motor skills, responsiveness, and language skills. The ability to grasp an object,
crawl up stairs, or search for a hidden toy—items that appear on the Bayley-III—are not measured by
childhood intelligence tests. Instead, intelligence tests administered in childhood examine more complex
and abstract abilities such as verbal reasoning, verbal comprehension, and problem-solving.
If the Bayley-III does not predict later intelligence, why administer it? Infants whose performance is poor
relative to age norms may suffer from serious developmental problems that can be addressed through
intervention (Del Rosario et al., 2020). The abilities measured by the Bayley-III are critical indicators of
neurological health and are useful for charting developmental paths, diagnosing neurological disorders,
and detecting intellectual disabilities in infants and toddlers. Thus, the Bayley-III is primarily used as a
screening tool to identify infants who can benefit from medical and developmental intervention.
Information Processing as Intelligence
The challenge in determining whether intelligence in infancy predicts performance in childhood and
beyond rests in identifying measures that evaluate cognitive functioning from infancy through
childhood. Information processing abilities, such as those related to attention, working memory, and
processing speed, underlie performance in all cognitive tasks, including intelligence tests, and are
therefore important indicators of intellectual ability that are evident at birth and persist for a lifetime
(Baddeley et al., 2019; Bialystok, 2007; Rey-Mermet et al., 2019; Ristic & Enns, 2015).
Individuals who process information more efficiently are thought to acquire knowledge more quickly.
This is true for infants as well as for older children and adults. Indeed, information processing capacities
in infancy, such as attention, memory, and processing speed, have been shown to predict cognitive
ability and intelligence through late adolescence.
Information processing abilities can be assessed in simple ways that allow us to study intelligence in
infants who are too young to tell us what they think and understand. Infants’ visual reaction time (how
quickly they look when shown a stimulus) and preference for novelty (the degree to which they prefer
new stimuli over familiar ones) are indicators of attention, memory, and processing speed and have been
shown to predict intelligence in childhood and adolescence (Fagan, 2011). Habituation tasks also provide
information about the efficiency of information processing because they indicate how quickly an infant
learns: Infants who learn quickly look away from an unchanging stimulus (or habituate) rapidly.
Longitudinal studies suggest that infants who are fast habituators score higher on measures of
intelligence in childhood and adolescence than do those who are slower habituators (Kavšek, 2013;
Rose, Feldman, Jankowski, et al., 2012). One study demonstrated that, compared with average and slow
habituators, infants who were fast habituators had higher IQs and higher educational achievement when
they were followed up 20 years later in emerging adulthood (Fagan et al., 2007).
Other studies confirm that infant information processing abilities are associated with measures of
intelligence throughout life. Working memory and visuospatial short-term memory in infancy are
associated with IQ in fourth- and fifth-grade children (Giofrè et al., 2013). Working memory and
processing speed are also associated with intelligence in children and adults (Redick et al., 2012; Rose,
Feldman, Jankowski, Van Rossem, et al., 2012; Sheppard, 2008). Information processing skills in infancy
are effective predictors of intelligence in childhood, but these findings are generally the result of
laboratory research. Although pediatricians might test an infant’s attention and habituation as part of an
examination, there is no standardized information processing test of intelligence to apply to infants
comparable to the Bayley-III.
Child Care and Cognitive Development
Infants are immersed in a system of contexts that influence their development. Parents shape infants’
physical world, providing food, health care, a home, and stimulation that influences their cognitive
development. Infants also are influenced by the child care context.
In the United States, more than half of all mothers of infants under 1 year old, and over two-thirds of
mothers of children under 6, are employed (U.S. Bureau of Labor Statistics, 2016). The infants and young
children of working mothers are cared for in a variety of settings: in center-based care, in the home of
someone other than a relative, or with a relative such as a father, grandparent, or older sibling (Federal
Interagency Forum on Child and Family Statistics, 2014). A common misconception is that nonfamilial
center-based care is damaging to children’s development and places children at risk for insecure
attachment. However, this belief is not supported by research.
One of the best sources of information about the effects of nonparental care is a longitudinal study of
over 1,300 children conducted by the National Institute of Child Health and Development (NICHD). This
study found infants’ developmental outcomes are influenced more by characteristics of the family, such
as parenting, maternal education, and maternal sensitivity, than by the type of child care (Axe, 2007;
Dehaan, 2006). Center-based care did not predispose infants to forming insecure attachments (Belsky,
2005; Harrison & Ungerer, 2002). Some research suggests that center-based care is associated with more
disobedience and aggression but is accompanied by greater sociability (Jacob, 2009). Other work
suggests that behavior problems may be more common in low-quality care but do not appear in highquality care (Gialamas et al., 2014; Huston et al., 2015). Indicators of high-quality child care include a low
child-to-teacher ratio and positive teacher–child interactions (Banghart et al., 2020).
Quality of child care matters. Infants and young children exposed to poor-quality child care score lower
on measures of cognitive and social competence, regardless of demographic variables such as parental
education and socioeconomic status (Banghart et al., 2020; NICHD Early Child Care Research Network,
2005). In contrast, high-quality child care that includes specific efforts to stimulate children is associated
with gains in cognitive and language development over the first 3 years of life and can even compensate
for lower quality and chaotic home environments (Berry et al., 2016; Gialamas et al., 2014; Mortensen &
Barnett, 2015; Watamura et al., 2011).
Child care quality has long-term effects as well. A recent study of Dutch infants showed that high-quality
care, defined as providing high levels of emotional and behavioral support, predicted children’s social
competence a year later; specifically, children who spent at least 3.5 days a week in care showed lower
p
y
; p
y,
p
y
levels of behavioral problems (Broekhuizen et al., 2018). Longitudinal research in Sweden showed that
older children and adolescents who had received high-quality care as infants and toddlers scored higher
on measures of cognitive, emotional, and social competence later in childhood (Andersson, 1989;
Broberg et al., 1997). In addition, a longitudinal analysis of over 1,200 children from the NICHD study
revealed that the quality of care predicted academic grades and behavioral adjustment at the end of
high school, at age 15 and 18, as well as admission to more selective colleges (Vandell et al., 2010, 2016).
The challenge is that high-quality child care is expensive. From 2012 to 2016, the annual cost of centerbased care in the United States ranged from about $6,000 in Arkansas to $22,000 in Washington, D.C.
(Child Care Aware of America, 2014; Schulte & Durana, 2016). In some countries, such as Sweden,
Norway, and Finland, child care is heavily subsidized by the government (Gothe-Snape, 2017). In the
United States, it remains a private responsibility. The few public subsidies for child care available in the
United States are tied to economic need and are mainly targeted at low socioeconomic status (SES)
families who receive other forms of public assistance. Children from low SES families and neighborhoods
tend to have poor access to quality care (Cloney et al., 2016). Child care settings vary dramatically in
form and quality, from large commercial centers to nonprofit facilities supported by churches and
community groups, to in-home and informal centers.
Poverty and Cognitive Development
Forty-five percent of U.S. children under 3 years of age (including two-thirds of Black, Hispanic, and
Native American children) live in low-income families (income less than $48,000 per year for a family of
four), and 23% live in poor families (income less than $24,000) (Heather & Yand, 2018). Children of color
are disproportionately likely to live in poverty (Figure 5.7). In 2013, the American Academy of Pediatrics
added child poverty to its Agenda for Children in recognition of poverty’s broad and enduring effects on
child health and development (American Academy of Pediatrics, 2017). Infants and children from poor
families experience higher rates of malnutrition, growth stunting, and susceptibility to illness than do
their peers (Yoshikawa et al., 2012).
Description
Figure 5.7 Percentage of Children in Low-Income and Poor Families by
Race/Ethnicity, 2016
Source: Koball and Jiang (2018.
Exposure to chronic long-term poverty has negative effects on brain growth and is associated with lower
volumes in parts of the brain associated with memory and learning, cognitive control, and emotional
processing (Johnson et al., 2016; Noble & Giebler, 2020; Wijeakumar et al., 2019). A longitudinal study of
77 children from birth to age 4 revealed a link between poverty and lower gray matter volume especially
in the frontal and parietal regions associated with executive function (Hanson et al., 2013). In another
study, 5-week-old infants in low SES homes tended to have smaller brain volumes than other infants,
suggesting that poverty may influence biological and cognitive development during the first few weeks
of life or earlier (Betancourt et al., 2016).
Poverty has a detrimental effect on children’s development and is associated
with deficits in memory and learning, cognitive control, and emotional
processing. Chronic poverty is especially damaging because the neurological
and cognitive deficits accumulate over childhood.
moodboard/Getty Images
The effects of socioeconomic status on development vary. SES is more closely related with brain
structure and cognition in children from poor homes than high SES homes (Hair et al., 2015; Noble et al.,
2015). That is, the detrimental effect of low SES contexts is a greater influence on children’s
development than the positive effect of high SES contexts. Chronic poverty is especially damaging
because the neurological and cognitive deficits accumulate over childhood (Dickerson & Popli, 2016).
One way in which poverty affects development is through the quality of parent–infant interactions and
infants’ exposure to language (Hackman et al., 2015). Infants in higher SES homes are talked to more and
the speech they hear is often more stimulating and supportive of language development than is the case
in lower SES homes (Fernald et al., 2013; Sheridan et al., 2012; Ursache & Noble, 2016).
Poverty is also thought to affect children’s outcomes indirectly by contributing to household chaos, a
combination of household instability and disorder (Berry et al., 2016; Marsh et al., 2020). Children reared
in economic uncertainty are more likely to experience disruptions in home settings and relationships
through household moves and adults moving in and out of the home (Pascoe et al., 2016). Impoverished
environments often include household crowding, lack of structure, and excessive ambient noise in the
home or neighborhood (Evans & Kim, 2013). Infants and children reared in environments of household
chaos may be overwhelmed by stimulation, combined with little developmentally appropriate support
with negative effects for cognitive development. The effects of a chaotic home environment begin early.
A chaotic environment has been shown to negatively affect visual processing speed for complex stimuli
in 5.5-month-old infants (Tomalski et al., 2017). Poverty has early effects on children’s brain development
that increase over time, with lifelong implications for cognitive and language development.
Thinking in Context: Lifespan Development
In what ways does cognitive development, such as sensorimotor stage or information processing
abilities, influence scores on infant intelligence measures? Do noncognitive abilities play a role in infant
intelligence scores? Why or why not?
Thinking in Context: Intersectionality
1. In what ways do race and ethnicity interact with SES to influence the challenges parents face in
providing quality caregiving and home environments? How might structural factors such as
neighborhoods and exposure to discrimination and bias influence caregiving environments?
2. What are some of the effects of poverty on infant and child development?
3. Identify factors within the family and home that can promote the development of infants and
children who are exposed to poverty.
4. How might child care act as a protective factor, aiding infants’ development? In ways are infants’
access to quality child care limited?
5. How might the extended family, neighborhood, and community help to buffer the effects of
challenging environments on development?
LANGUAGE DEVELOPMENT IN INFANCY AND TODDLERHOOD
LEARNING OBJECTIVE
5.5 Summarize the patterns of language development during infancy and toddlerhood.
“You just love to hear Mommy talk, don’t you?” Velma asked as newborn Jayson stared up at her. Is
Jayson attending to his mother? Is he interested in his mother’s speech? As described in Chapter 4,
hearing emerges well before birth, and evidence suggests that newborns can recall sounds heard in the
womb (Dirix et al., 2009). Jayson recognizes his mother’s voice and naturally tunes in, which will help him
learn language, a critical task for infancy and toddlerhood. Language development has important
implications for the child’s cognitive, social, and emotional development. Gaining the ability to use
words to represent objects, experiences, thoughts, and feelings permits children to think and to
communicate with others in increasingly flexible and adaptive ways.
Early Preferences for Speech Sounds
Newborn infants are primed to learn language. Recall from Chapter 4 that neonates naturally attend to
speech and prefer to hear human speech sounds, especially their native language, as well as stories and
sounds that they heard prenatally (May et al., 2018). Infants naturally notice the complex patterns of
sounds around them and organize sounds into meaningful units (Saffran, 2020). They recognize
frequently heard words, such as their names. By 4½ months of age, infants will turn their heads to hear
their own names but not to hear other names, even when the other names have a similar sound pattern
(e.g., Annie and Johnny) (Mandel et al., 1995). At 6 months of age, infants pay particular attention to
vowel sounds and, at 9 months, consonants (Kuhl, 2015).
Although infants can perceive and discriminate sounds that comprise all human languages at birth, their
developing capacities and preferences are influenced by context (Hoff, 2015). The Japanese language
does not discriminate between the consonant sounds of “r” in
and “l” in . Japanese adults who are
learning English find it very difficult to discriminate between the English pronunciations of these “r” and
“l” sounds, yet up until about 6 to 8 months of age, Japanese and U.S. infants are equally able to
distinguish these sounds. By 10 to 12 months, however, discrimination of “r” and “l” improves for U.S.
infants and declines for Japanese infants. This likely occurs because U.S. infants hear these sounds often,
whereas Japanese infants do not (Kuhl et al., 2006). As they are exposed to their native language, they
become more attuned to the sounds (and distinctions between sounds) that are meaningful in their own
language and less able to distinguish speech sounds that are not used in that language (Werker et al.,
2012). Native-language discrimination ability between 6 and 7 months predicts the rate of language
growth between 11 and 30 months (Kuhl, 2015).
rip
lip
Infants’ speech discrimination abilities remain malleable in response to the social context (Kuhl, 2016). In
one study, Kuhl and her colleagues exposed 9-month-old English-learning American infants to 12 live
interaction sessions with an adult speaker of Mandarin Chinese over the course of 4 to 5 weeks (Kuhl et
al., 2003). After the sessions, the infants were tested on a Mandarin phonetic contrast that does not
occur in English. The infants discriminated the contrast as well as same-aged Mandarin-learning infants
and retained the contrast for several days. The relevance of context is also illustrated by the infants’ loss
of the ability to discriminate the Mandarin contrast several days after training, presumably in the
absence of ongoing exposure to the Mandarin language (Fitneva & Matsui, 2015).
Social interaction is vital to language learning. In the study just described, the English-learning infants
did not learn the Mandarin phonetic contrast when they were exposed to it only by audio or video. Live
interaction may have increased infants’ motivation to learn by increasing their attention and arousal. Or
perhaps live interaction provides specific information that fosters learning, like the speaker’s eye gaze
and pointing coupled with interactive contingency (Kuhl et al., 2003).
In addition, social input, such as the quality of mother–infant interactions, plays a critical role in
determining the timing of infants’ narrowing of speech sound discrimination. Specifically, infants who
experience high-quality interactions with their mothers, characterized by frequent speech, show a
narrowing earlier, as early as 6 months of age (Elsabbagh et al., 2013).
Prelinguistic Communication
At birth, crying is the infant’s only means of communication. Infants soon learn to make many more
sounds, like gurgles, grunts, and squeals. Between 2 and 3 months of age, infants begin cooing, making
deliberate vowel sounds like “ahhhh,” “ohhhh,” and “eeeee.” Infants’ first coos sound like one long vowel.
These vocal sounds are a form of vocal play; they are likely to be heard when babies are awake, alert,
and contented. At the cooing stage, infants already use pauses that are consistent with the turn-taking
pattern of spoken conversations. With age, the quality of coos changes to include different vowel-like
sounds and combinations of vowel-like sounds (Owens, 2020). Babbling, repeating strings of consonants
and vowels such as “ba-ba-ba” and “ma-ma-ma,” begins to appear at about 6 months of age.
At first, babbling is universal. All babies do it, and the sounds they make are similar no matter what
language their parents speak or in what part of the world they are raised. But infants soon become
sensitive to the ambient language around them, and it influences their vocalizations (Chen & Kent,
2010). In one study, French adults listened to the babbling of a French 8-month-old and a second 8month-old from either an Arabic-speaking or a Cantonese-speaking family. Nearly three-quarters of the
time, the adults correctly indicated which baby in the pair was French (Boysson-Bardies et al., 1984). By
the end of the first year, infants’ babbling sounds more like real speech as they begin to vary the pitch of
their speech in ways that reflect the inflections of their native languages (Andruski et al., 2013). In
spoken English, declarative sentences are characterized by pitch that falls toward the end of the
sentence, whereas in questions the pitch rises at the end of the sentence. Older babies’ babbling mirrors
these patterns when they are raised by English-speaking parents, while babies reared with Japanese or
p
y
y g
p
gp
,
p
French as their native languages show intonation patterns similar to those of the respective languages
(Levitt et al., 1992). Longitudinal observations of infants raised in Catalan-speaking environments
likewise show that their babbling shifts to mirror intonations in native speech (Esteve-Gilbert et al.,
2013).
Language acquisition, as mentioned, is a socially interactive process: Babies learn by hearing others
speak and by noticing the reactions that their vocalizations evoke in caregivers (Hoff, 2015; Kuhl, 2016).
Social interaction elicits cooing, and infants modify their babbling in response to caregiver interactions
(Tamis-LeMonda et al., 2014). When mothers of 9½-month-old infants speak in response to their infants’
babbling, infants restructure their babbling, changing the phonological pattern of sounds in response to
their mothers’ speech (Goldstein & Schwade, 2008). Babbling repertoires reflect infants’ developing
morphology and are a foundation for word learning (Ramsdell et al., 2012).
Babies learn language by hearing others speak and by modifying their
babbling in response to caregiver interactions.
Eric Scouten/Alamy Stock Photo
Putting Words Together
Language development follows a predictable pattern from prelinguistic communication, to learning
words, to stringing words together to communicate with others.
First Words
Eleven-month-old William was wide-eyed as his father handed him a ball and said, “Ball!” “Ba!” said
William. William now understands many words and is beginning to try to utter them. Throughout
language development, babies’ receptive language (what they can understand) exceeds their
productive language (what they can produce themselves) (Tamis-Lemonda & Bornstein, 2015). That is,
infants understand more words than they can use. Research suggests that infants may understand some
commonly spoken words as early as 6 to 9 months of age, long before they are able to speak (Bergelson
& Swingley, 2012; Dehaene-Lambertz & Spelke, 2015).
At about 1 year of age, the average infant speaks his or her first word. At first, infants use one-word
expressions, called holophrases, to express complete thoughts. A first word might be a complete word
or a syllable. Usually, the word has more than one meaning, depending on the context in which it is
used. “Da” might mean, “I want that,” “There’s Daddy!” or “What’s that?” Caregivers usually hear and
g
,
,
y
g
y
understand first words before other adults do. The first words that infants use are those that they hear
often or are meaningful for them, such as their own name, the word , or the word for their caregiver.
Infants reared in English-speaking homes tend to use nouns first, as they are most concrete and easily
understood (Waxman et al., 2013). The word
refers to a concrete thing—an animal—and is easier to
understand than a verb, such as
. In contrast, infants reared in homes in which Mandarin Chinese,
Korean, or Japanese is spoken tend to learn verbs very early in their development in response to the
greater emphasis on verbs in their native languages (Waxman et al., 2013).
goes
dog
no
Regardless of what language a child speaks, early words tend to be used in the following ways
(MacWhinney, 2015; Owens, 2020):
Request or state the existence or location of an object or person by naming it (car, dog, outside).
Request or describe the recurrence of an event or receipt of an object (again, more).
Describe actions (eat, fall, ride).
Ask questions (What? That?).
Attribute a property to an object (hot, big).
Mark social situations, events, and actions (no, bye).
Learning Words: Semantic Growth
“I can’t believe how quickly Matthew picks up new words. It’s time for us to be more careful about what
we say around him,” warned Elana. Her husband agreed, “He’s only 2 years old and he has quite a
vocabulary. Who would think that he’d learn so many words so quickly?” By 13 months of age, children
begin to quickly learn the meaning of new words and understand that words correspond to particular
things or events (Woodward et al., 1994). Most infants of Matthew’s age expand their vocabularies
rapidly, often to the surprise of their parents. Infants learn new words through fast mapping, a process
of quickly acquiring and retaining a word after hearing it applied a few times (Kan & Kohnert, 2008;
Marinellie & Kneile, 2012). At 18 months, infants are more likely to learn a new word if both they and the
speaker are attending to the new object when the speaker introduces the new word (Baldwin et al.,
1996). Two-year-olds have been shown to be able to learn a word even after a single brief exposure
under ambiguous conditions (Spiegel & Halberda, 2011) or after overhearing a speaker use the word
when talking to someone else (Akhtar et al., 2001). Between 24 and 30 months, infants can learn new
words even when their attention is distracted by other objects or events (Moore et al., 1999). Children’s
knowledge and interests influence their vocabulary development. They are more likely to learn words
that are related to those they know and label objects, actions, and events that they find interesting
(Mani & Ackermann, 2018).
Fast mapping improves with age and accounts for the vocabulary spurt, also known as a naming
explosion—a period of rapid vocabulary learning that occurs between 16 and 24 months of age (Owens,
2020). During this period, infants apply their word-learning strategies to learn multiple words of varying
difficulty seemingly at once. Within weeks, a toddler may increase her vocabulary from 50 words to over
400 (Bates et al., 1988). As shown in Figure 5.8, infants vary in the speed of word acquisition, with some
showing a rapid increase in vocabulary before others (Samuelson & McMurray, 2017). In addition,
although fast mapping helps young children learn many new words, their own speech lags behind what
they can understand because young children have difficulty retrieving words from memory (McMurray,
2007). The speed at which young children acquire words during the vocabulary spurt predicts the size of
their vocabulary as preschoolers at 54 months of age (Rowe, 2012). That is, children who rapidly expand
their knowledge of words during the vocabulary spurt tend to have larger vocabularies in preschool than
their peers who acquire new words at a slower pace.
Description
Figure 5.8 Number of Words Known as a Function of Time for Individual
Children
Source: Samuelson & McMurray (2017).
As children learn words, we see two interesting kinds of mistakes that tell us about how words are
acquired (Gershkoff-Stowe, 2002). Underextension refers to applying a word more narrowly than it is
usually applied so that the word’s use is restricted to a single object. Cup might refer to Daddy’s cup but
not to the general class of cups. Later, the opposite tendency appears. Overextension refers to applying
a word too broadly. Cow might refer to cows, sheep, horses, and all farm animals. Overextension
suggests that the child has learned that a word can signify a whole class of objects. As children develop
a larger vocabulary and get feedback on their speech, they demonstrate fewer errors of overextension
and underextension (Brooks et al., 2014).
Two-Word Utterances
At about 21 months of age, or usually about 8 to 12 months after they say their first word, most children
compose their first simple two-word sentences, such as “Kitty come,” or “Mommy milk.” Telegraphic
speech, like a telegram, includes only a few essential words. Like other milestones in language
development, telegraphic speech is universal among toddlers. Children around the world use two-word
phrases to express themselves.
Language development follows a predictable path, as shown in Table 5.3. Between 20 and 30 months of
age, children begin to follow the rules for forming sentences in a given language. Soon they become
more comfortable with using plurals, past tense, articles (such as and
), prepositions (such as and
), and conjunctions (such as
and
). By 2½ years of age, children demonstrate an awareness of
the communicative purpose of speech and the importance of being understood (Owens, 2020). In one
experiment, 2½-year-old children asked an adult to hand them a toy. A child was more likely to repeat
and clarify the request for the toy when the adult’s verbal response indicated misunderstanding of the
child’s request (“Did you say to put the toy on the shelf?”) than when the adult appeared to understand
the request, regardless of whether the adult gave the child the toy (Shwe & Markman, 1997).
on
Table 5.3 Language Milestones
and
but
a
the
in
Age
2–3 months
6 months
1 year
Language Skill
Cooing
Babbling
First word
Holophrases
16–24 months
Vocabulary spurt
Learn new words by fast mapping
Underextension
Overextension
21 months
Telegraphic speech
21–30 months Syntax
Infant Gesture and Sign Language
Infants often use simple gestures, such as pointing and nodding the head, before they can speak. The
use of gestures and the ability to jointly attend, directing an adult’s attention to an object, predicts later
language development (Cameron-Faulkner, 2020; Salo et al., 2018, 2019). Infants’ early use of gesture to
communicate has led some scientists to examine whether infants can be taught to communicate with
symbolic gestures, sometimes referred to as infant sign language or the baby signing movement.
The assumption behind baby signing is that the cognitive and gross motor skills needed for signing
develop before the relatively fine motor control of the mouth, tongue, and breath needed to articulate
speech (Goodwyn & Acredolo, 1998). Researchers Linda Acredolo and Susan Goodwyn demonstrated
that babies readily acquire symbolic gestures when exposed to the enhanced gestural training that they
refer to as baby signs (Acredolo et al., 2009). They propose that the rewards of baby signing include
larger and more expressive vocabulary, advanced mental development, improved parent–child
relationships, and fewer tantrums and behavior problems (Acredolo & Goodwyn, 1988; Goodwyn &
Acredolo, 1998). Based on their findings, Acredolo and Goodwyn created a signing program for infants
with videos, classes, books, and cue cards (Acredolo et al., 2009). Numerous companies have been
created to promote and sell baby signing materials, often advertising benefits such as facilitating spoken
language, reducing tantrums, and increasing IQ.
It is generally recognized that gesture and language are linked and that babies naturally make early
gestures that precede their use of language (Cameron-Faulkner, 2020; Iverson & Goldin-Meadow, 2005).
Sensitive responses from caregivers tend to result in more pointing and gesturing from infants,
suggesting that gestures are a form of communication (Vallotton et al., 2017). But will baby signing
programs and videos accelerate language and cognitive development? One review of 33 websites
associated with various baby signing products revealed that all promoters claimed benefits such as
faster language development, and many claimed to foster cognitive and emotional development,
including higher IQs, improvements in parent–child interactions, and fewer child tantrums (Nelson et al.,
2012). Yet almost none provided evidence to support these claims. A review of research studies
examining the outcomes of baby signing programs found that although some of the studies suggested
some benefits, nearly all contained methodological weaknesses such as a lack of control groups or no
random assignment (see Chapter 1), suggesting insufficient evidence to support these claims (Johnston,
2005).
More recently, a longitudinal study tested the effects of baby signing products. Infants were followed
from 8 months of age until 20 months of age (Kirk et al., 2013). Babies were randomly assigned to one of
three conditions: baby sign training, verbal training (i.e., mothers modeled words without signs), and
nonintervention. At 20 months of age, the language development was similar for all babies, regardless of
intervention. Encouraging gestures did not result in higher scores on language measures, providing no
support for the claims of baby signing proponents.
Nevertheless, many parents report that baby signing has improved their child’s ability to communicate,
cognitive ability, and overall parent–infant interactions (Doherty-Sneddon, 2008; Mueller & Sepulveda,
2014). Although U.K. infants enrolled in a baby signing class showed no differences in language
development compared with their nonsigning peers, mothers who enrolled their infants in the baby
signing class tended to use more mental terms and refer to thinking (“You want the toy, huh?”) in their
infant-directed interactions (Zammit & Atkinson, 2017). Baby signing may not have research support for
accelerating language development, but if it promotes frequent parent–infant interaction, does not rush
or pressure infants, and is helpful in parents’ estimation, there is no reason to discourage its use.
Although signing may not accelerate language development, it offers
opportunities for parent–infant interaction and play.
Jamie Grill/Getty Images
Language Development in Bilingual Infants
From birth, infants attend to speech sounds. Through exposure to speech, they rapidly learn the
consonant and vowel sounds that comprise language. How is language learning influenced by exposure
to two languages? Brain scans suggest that 12-month-old bilingual infants’ responses to language are
similar to those of monolingual infants, suggesting that they are on the same timetable for language
learning (Ferjan Ramírez et al., 2017). Notably, bilingual infants do retain the ability to discriminate
phonetic speech sounds of other languages long after monolingual peers have narrowed their
perception to native-language sounds (Garcia-Sierra et al., 2011; Petitto et al., 2012).
Language development is promoted through exposure to speech during frequent, high-quality social
interactions. In bilingual babies, the amount of infant-directed speech heard in one-to-one interactions
influences the growth of that language but is unrelated to growth of the second language (Kuhl &
Ramirez, 2016). Hearing lots of high-quality Spanish in interactions with a caregiver predicts the growth
of Spanish but not English. Bilingual infants’ brain responses to hearing each language vary with the
amount and quality of speech they hear in each (Garcia-Sierra et al., 2011). Language growth, therefore,
is related to the quality and quantity of speech heard, whether in one language or two.
Typically infants exposed to two languages from birth babble and produce their first words at the same
as those exposed to one language. Bilingual infants’ vocabulary develops in similar ways as monolingual
infants (Höhle et al., 2020; Kuhl & Ramirez, 2016). Although bilingual infants show a smaller vocabulary
than monolingual infants on a single language when both languages are considered, bilingual children
do not lag behind monolingual peers (Hoff et al., 2012). Combined across both languages, bilingual
children’s vocabulary tends to be equal or greater than those of monolingual children (Hoff & Core,
2015). Infants’ language skills reflect the quantity of language that they hear. The rate of vocabulary and
grammatical growth in bilingual children correlates with quality and quantity of speech that they hear in
each language (Ramírez-Esparza et al., 2017). Moreover, some research suggests that bilingual infants
are better at learning new words than their monolingual peers (Singh et al., 2018). Their exposure to the
sounds of multiple languages contributes to their ability to flexibly learn new sounds.
Language Development in Deaf Infants
About 2 in 1,000 U.S. infants are born with profound hearing loss (Centers for Disease Control and
Prevention, 2019). We have seen that infants are sensitive to language from birth, and language
develops rapidly over the first year of life, placing deaf infants at risk for impaired language
development. Advances in technology have led nearly all industrialized countries to adopt policies for
universal neonatal hearing screening (National Center for Hearing Assessment and Management, 2019)
and provide early intervention promoting access to visual and/or spoken language (Lederberg et al.,
2013). Researchers have documented dramatic improvements in language outcomes when losses are
identified at birth and intervention implemented by 6 months of age (Cole & Flexer, 2016). Typically,
infants with hearing loss wear hearing aids and those with profound hearing loss eventually obtain
cochlear implants, electrical devices that convert auditory information into electric signals that are
transmitted to the brain. The U.S. Food and Drug Administration advises cochlear implantation after 12
months of age, but research suggests that the earlier age of cochlear implantation, as early as 6 months
of age, improves language outcomes (McKinney, 2017). However, early administration of cochlear
implants is often not covered by health insurance, limiting access to early intervention to families with
greater economic means.
Infants with hearing loss do not experience the range of sensory input that hearing infants receive. Early
hearing loss affects the development of cognitive skills, such as memory, attention, learning, and
information processing, skills that are also essential for speech and spoken language development
(Kronenberger & Pisoni, 2018). Moreover, auditory deprivation early in life may affect brain
development, reducing the neurological ability to detect and respond to speech signals and making it
difficult to learn language (Wang et al., 2018). We have seen that sensory deprivation at birth has
dramatic effects on the organization of the brain that interfere with its normal development.
In addition to the availably of early intervention, infants’ outcomes are influenced by contextual factors
such as the availability and use of family support from professionals, access to and the ability of family
members to learn sign language, and access to professional services and technology (Lederberg et al.,
2013). Language environments vary and children with hearing loss may be especially sensitive to
variations in environmental quality, such as the quality and quantity of parent speech (Levine et al.,
2016). There is a dynamic web of factors, such as parental knowledge and involvement, socioeconomic
status, access to quality early childhood education, and community support.
Thinking in Context: Lifespan Development
1. What role do other domains of development hold in influencing infants’ language development?
Consider motor development, perception, and cognition. How might advances in these domains
influence infants’ emerging language abilities?
2. Infants are primed to learn language and play an active role in their language development.
Explain and provide examples considering dual language learners, deaf infants, or infant gesture.
INFLUENCES ON LANGUAGE DEVELOPMENT: INTERACTIONIST
PERSPECTIVE
LEARNING OBJECTIVE
5.6 Compare and contrast influences on language development.
Over the first 2 years of life, children transform from wailing newborns who communicate their needs
through cries to toddlers who can use words to articulate their needs, desires, and thoughts.
Developmental scientists have offered several explanations for infants’ rapid acquisition of language,
some emphasizing the role of the environment and others focusing on biological factors. Recall our
discussion of the nature–nurture issue in Chapter 1. Most developmental scientists believe that nature
(biology) and nurture (environment) interact in dynamic ways to influence development.
From an interactionist standpoint, language development is a complex process reflecting the dynamic
interplay of two factors: children’s biological capacities and the social context in which they are reared. A
newborn’s ability to discriminate a wide variety of speech sounds and to prefer human speech over
recorded sounds—as well as to prefer the sounds and patterns of their native language over those of
other languages—suggests an inborn sensitivity to language. Yet the language that an infant learns and
the pace of learning are influenced by environmental factors. Let’s explore biological and contextual
contributors to language.
Nativism
Nativist theorists, like Noam Chomsky, believe that development is an innate process. Chomsky (1959,
2017) argued that language use comprises behavior that is too complex to be learned so early and
quickly via conditioning alone. He noted that all young children grasp the essentials of grammar, the
rules of language, at an early age and that the languages of the world have many similarities. The human
brain thus has an innate capacity to learn language.
Chomsky believed that infants are born with a language acquisition device (LAD), an innate facilitator of
language that permits infants to quickly and efficiently analyze everyday speech and determine its rules,
regardless of whether their native language is English, German, Chinese, or Urdu (Yang et al., 2017). The
LAD has an innate storehouse of rules, universal grammar, that apply to all human languages. When
infants hear language spoken, they naturally notice its linguistic properties, and they acquire it.
Language, therefore, is a biologically driven cognitive mechanism of brain development that is triggered
by exposure to language (Friederici, 2017).
The nativist perspective can account for children’s unique utterances and the unusual grammatical
mistakes they make in speaking because children are biologically primed to learn language and do not
rely on learning. Critics point out that Chomsky’s nativist perspective does not explain the process of
language development and how it occurs (Ibbotson & Tomasello, 2016). Researchers have not identified
the LAD or universal grammar that Chomsky thought underlies all languages. In addition, there are more
individual differences in language learning and in languages than Chomsky proposed (Dąbrowska,
2015). Moreover, language does not emerge in a finished form. Instead, children learn to string words
together over time based on their experiences as well as through trial and error (Tomasello, 2012).
Finally, it appears that language learning does not occur as quickly or effortlessly as Chomsky described
(Miller, 2016).
Evolution and Brain Development
Evolutionary developmental theorists explain language as having evolved through natural selection.
Language gave some of our early human ancestors an advantage in survival and reproduction over
those who did not have language (Berwick & Chomsky, 2016; Hauser et al., 2014). Specifically, language
evolved as an adaptation that fulfilled early humans’ need to communicate information that was more
complex than could be conveyed by simple calls and hoots (Tamariz & Kirby, 2016). Language may have
emerged with increases in the size of human communities and the corresponding complexity of social
dynamics, as well as humans’ increasingly large, more sophisticated brains (Aiello & Dunbar, 1993;
Turnbull & Justice, 2016).
The brain is wired for language at birth. Speech sounds produce more activity in the left hemisphere of
newborns’ brains, while nonspeech sounds elicit more activity in the right hemisphere (Vannasing et al.,
2016). In response to hearing language, 3-month-old infants show functional neural activity that is
similar but less refined, focused, and organized than that of adults (Dehaene-Lambertz, 2017). Adult
language, too, is largely governed by the left hemisphere, and cortical activity in language areas
increases from infancy through adulthood (Paquette et al., 2015). Two areas in the left hemisphere of the
brain are vital for language and distinguish humans from other primates: Broca’s and Wernicke’s areas
(Friederici, 2017). Broca’s area controls the ability to use language for expression. Damage to this area
inhibits the ability to speak fluently, leading to errors in the production of language. Wernicke’s area is
responsible for language comprehension. Damage to Wernicke’s area impairs the ability to understand
the speech of others and sometimes affects the ability to speak coherently.
Although the brain plays a crucial role in language capacities, it cannot completely account for language
development. Recent research has identified multiple genes associated with language development that
work together in an epigenetic fashion, influenced by environmental factors (Dediu & Christiansen,
2016; Fisher, 2017). In addition, experience influences the brain architecture that supports language
development (Westermann, 2016).
We have seen that infants’ ability to detect sounds not used in their native language declines throughout
the first year of life, suggesting that contextual factors—specifically, exposure to the native language—
influence older infants’ sensitivity to speech sounds (Posner, 2001; Sansavini et al., 1997). At the same
time, information processing factors largely dependent on neurological development, such as attention
and memory, affect how infants comprehend and respond to social interaction and other contextual
influences on language development (Perszyk & Waxman, 2018). The statistical learning abilities that
enable infants to see patterns and learn quickly are also associated with rapid language learning (Lany et
al., 2018).
Social Learning
Baby Howie gurgles, “Babababa!” His parents encourage him excitedly, “Say bottle; ba-ba!” Howie
squeals, “Babababa!” “Yes! You want your ba-ba!” Parents play an important role in language
development. They provide specific instruction and communicate excitement about their infants’
developing competence, encouraging infants to practice new language skills. Learning theorist B. F.
Skinner (1957) proposed that language, just like all other behaviors, is learned through operant
conditioning: reinforcement and punishment. From birth, infants make sounds at random. Caregivers
respond to infants’ early utterances with interest and attention, imitating and reinforcing their verbal
behavior (Pelaez et al., 2011; Petursdottir & Mellor, 2017). Infants repeat the sounds. Caregivers then
reward sounds that resemble adult speech with attention, smiles, and affection. Infants imitate sounds
that adults make and repeat sounds that are reinforced. From this perspective, imitation and
reinforcement shape children’s language development. The quantity and quality of the parents’ verbal
interactions with the child and responses to the child’s communication attempts influence the child’s
rate of language development (Hoff, 2015).
In the view of learning theorists, then, infants learn by observing the world around them and adults
encourage and reinforce their language learning. Critics point out that learning theory cannot account
for all of language development because it cannot account for the unique utterances and errors that
young children make (Berwick et al., 2013). Word combinations are complex and varied—they cannot be
acquired solely by imitation and reinforcement. Toddlers often put words together in ways that they
likely have never heard (e.g., “Mommy milk”). Young children make grammatical errors, such as “mouses”
instead of “mice” or “goed” instead of “went,” that cannot be the result of imitation. If language is
learned through imitation, how do young children make grammatical errors that they have never heard
spoken? Young children repeat things that they hear (sometimes to parents’ chagrin!), but they also
construct new phrases and utterances that are unique. Reinforcement from parents and caregivers is
powerful encouragement for children, but language development cannot be completely explained by
learning theory alone. Despite wide variations in circumstances, living situations, and contexts, infants
g
y
p
,
g
,
,
around the world achieve language milestones at about the same ages, suggesting a biological
component to language development.
Infant-Directed Speech
Language development occurs in a social context. Most adults naturally speak to young infants in a singsong way that attracts their attention. Infant-directed speech uses repetition, short words and
sentences, high and varied pitch, and long pauses (Thiessen et al., 2005). Infants prefer listening to
infant-directed speech than to typical adult speech, and they prefer adults who use infant-directed
speech (Schachner & Hannon, 2011). EEG recordings show that babies—even newborns—demonstrate
more neural activity in response to infant-directed speech than adult speech, suggesting that they are
better able to attend to it and distinguish the sounds (Háden et al., 2020; Peter et al., 2016). Infantdirected speech exaggerates sounds, helping infants hear and distinguish sounds, and enables them to
map sounds to meanings (Estes & Hurley, 2013; Kitamura & Burnham, 2003; Thiessen et al., 2005). In one
study, 7- and 8-month-old infants were more likely to learn words presented by infant-directed speech
than those presented through adult-directed speech (Singh et al., 2009).
Adults naturally talk to infants, and infant-directed speech has been documented in many languages
and cultures (Bryant et al., 2012; Kuhl et al., 1997). Comparisons of mothers from Fiji, Kenya, and the
United States show the use of high-pitched speech, which is characteristic of infant-directed speech,
with infants (Broesch & Bryant, 2015). The pattern of infant-directed speech is similar across cultures
such that adults can discriminate it from adult-directed speech even while listening to a language they
do not speak. When adults in the Turkana region of northwestern Kenya listened to speech produced in
English by American mothers, they were able to discriminate between infant-directed and adult-directed
speech, suggesting that infant-directed speech is recognizable to adults of many cultures (Bryant et al.,
2012). Despite this, adults of different cultures vary in their interactions with infants.
Through infant-directed speech, adults attract infants’ attention by using
shorter words and sentences, higher and more varied pitch, repetition, and a
slower rate. Infants prefer listening to infant-directed speech, and infantdirected speech appears cross-culturally.
iStock/damircudic
Cultural Differences in Infant-Directed Speech
Cultures differ in the use of infant-directed speech. For example, in Samoa, infants are not addressed
directly by caregivers until they begin to crawl. Parents tend to interpret their vocalizations as indicators
of physiological state rather than as attempts to communicate. Because of the status hierarchy in Samoa,
child-directed speech is uncommon in adults because it would reflect someone of higher status (i.e., an
adult) adjusting his or her speech to someone of lower status (Ochs & Schieffein, 1984). Instead, older
children are tasked with responding to infants’ utterances, and it is largely older children who talk with
infants (Lieven & Stoll, 2010). Similarly, the Kaluli of Papua New Guinea do not engage in infant-directed
speech (Fitneva & Matsui, 2015). Infants are held oriented outward rather than toward the mother. When
infants are addressed by others, the mother speaks for the infant in a high-pitched voice but does not
use simplified language. Only when children themselves begin to talk do parents start talking to them,
and then they focus on teaching them what to say (Ochs & Schieffein, 1984).
Culture even shapes the types of words that infants learn. In Asian cultures that stress interpersonal
harmony, such as Japan, China, and Korea, children tend to acquire verbs and social words much more
quickly than do North American toddlers (Gopnik & Choi, 1995; Tardif et al., 2008). In another study, U.S.
mothers responded to infant object play more than social play, whereas Japanese mothers responded
more to social play (Tamis-LeMonda et al., 1992). North American infants’ first words tend to include
more referential language, or naming words such as “ball,” “dog,” “cup,” and the like, while Japanese
infants tend to use more expressive language, or words that are used mainly in social interaction, such as
“please” and “want” (Fernald & Morikawa, 1993). Italian-, Spanish-, French-, Dutch-, Hebrew-, and
English-speaking infants tend to display a preference for using more nouns than verbs (Bassano, 2000;
Bornstein, Cote, et al., 2004; de Houwer & Gillis, 1998; Maital et al., 2000; Tardif et al., 1997). Cultures vary
in common practices and contexts of infant-directed communication, yet all infants learn language,
supporting the powerful role of maturation.
Although parents from different cultures vary in how often they respond to their infants, parental
response patterns that are warm, consistent, and contingent on infant actions are associated with
positive language development in infants across cultures (Tamis-LeMonda et al., 2014). In a study of six
cultural communities, mothers from Berlin and Los Angeles were more likely to respond to infant
nondistress vocalizations and gazes than were mothers from Beijing and Delhi, as well as Nso mothers
from various cities in Cameroon (Kärtner et al., 2008). In contrast, Nso mothers responded more often to
infant touch than did mothers from other cultures. Although parental responsiveness may look different
and take different forms across cultures, its benefits generalize across families from varying cultural
communities and socioeconomic strata (Rodriguez & Tamis-LeMonda, 2011).
Parents from different cultures vary in how often they respond to their
infants, but parental response patterns that are warm, consistent, and
contingent on infant actions predict positive language development in
infants across cultures.
Spencer Robertson/Newscom
Parental Responsiveness
Babies learn language by interacting with more mature, expert speakers who can speak at their
developmental level. When babies begin to engage in canonical babbling, a type of babbling with wellformed syllables that sounds remarkably like language, parents, regardless of socioeconomic status,
ethnicity, and home environment, tune in and treat the vocalizations in a new way (Oller et al., 2001).
Because the utterances sound like words, parents help infants to associate the word-like utterances with
objects and events, encouraging vocabulary development.
Parents often adjust their infant-directed speech to match infants’ linguistic needs by using longer and
more complicated words and sentences as infants’ comprehension increases (Englund & Behne, 2006;
Sundberg, 1998). Even as infants learn speech, they continue to display preferences for some features of
infant-directed speech. A study of 12- and 16-month-old infants indicated that they preferred the high
pitch and pitch variability of infant-directed speech but not the shorter utterances or simplified syntax
(Segal & Newman, 2015).
Parental responsiveness to infants’ vocalizations predicts the size of infants’ vocabularies, the diversity of
infants’ communications, and the timing of language milestones (Tamis-LeMonda et al., 2014). One study
showed that infants of highly responsive mothers achieved language milestones such as first words,
vocabulary spurt, and telegraphic speech at 9 to 13 months of age, which was 4 to 6 months earlier than
infants of low-responsive mothers (Tamis-LeMonda et al., 2001). Fathers’ responsiveness to their 2- and
3-year-olds predicted toddlers’ cognitive and language abilities (Tamis-LeMonda et al., 2004). Parental
responsiveness is also associated with the language skills of adopted children, supporting the contextual
influence of parents (Stams, Juffer, & van IJzendoorn, 2002).
The quality of language input from parents and the number of words children hear is related to their
vocabulary size at age 2 (Hoff et al., 2002). Children whose mothers address a great deal of speech to
them develop vocabulary more rapidly, are faster at processing words they know, and are faster at
producing speech than children whose mothers speak to them less often (Hurtado et al., 2008; Weisleder
& Fernald, 2013). The number of words and different grammatical structures used in maternal speech, as
well as grammatical complexity, predict the size of children’s vocabulary and understanding of grammar
(Hadley et al., 2011; Huttenlocher et al., 2010).
Although parents do not reliably reinforce correct grammar, they tend to communicate in ways that tell
young children when they have made errors and show how to correct them (Saxton, 1997). Adults often
respond to children’s utterances with expansions, which are enriched versions of the children’s
statements. If a child says, “bottle fall,” the parent might respond, “Yes, the bottle fell off the table.”
Adults also tend to recast children’s sentences into new grammatical forms. “Kitty go,” might be recast
into, “Where is the kitty going?” When children use grammatically correct statements, parents maintain
and extend the conversation (Bohannon & Stanowicz, 1988). When adults recast and expand young
children’s speech, the children tend to acquire grammatical rules more quickly and score higher on tests
of expressive language ability than when parents rely less on these conversational techniques (Abraham
et al., 2013; Bohannon et al., 1996).
In sum, an interactionist approach to language development emphasizes the dynamic and reciprocal
influence of biology and context. Infants are equipped with biological propensities and information
processing capacities that permit them to perceive and analyze speech and learn to speak. Infants are
motivated to communicate with others, and language is a tool for communication. Interactions with
others provide important learning experiences, which help infants expand their language capacities and
learn to think in ways similar to members of their culture (Fitneva & Matsui, 2015).
Thinking in Context: Biological Influences
Language is biologically programmed to unfold without instruction. Discuss this statement, applying
what you know about biological views of language, such as nativism and evolutionary developmental
psychology. Do you agree or disagree with this perspective? Explain.
Thinking in Context: Applied Developmental Science
What can parents do to promote language development in their infants? Provide advice to parents in
light of the interactionist perspective, including the role of infant-directed speech and parental
responsiveness.
APPLY YOUR KNOWLEDGE
One-and-a-half-year-old Joshua attends an exclusive local nursery school called Three Trees, all day
Monday through Friday. Three Trees Nursery School emphasizes interactive play with peers. The staff is
culturally diverse and the child-to-staff ratio is 1-to-3, which allows each child to have individualized
care, attention, and specialized learning opportunities.
The staff at Three Trees are informed about new and important findings from research in child
development. They are trained in effective ways to promote and develop skills in attention, memory, and
categorization. Joshua’s mother, a lawyer, chose Three Trees because of its emphasis on the early
introduction of learning concepts. The school has an indoor classroom accompanied with stimulating
toys and an ample acre-large play area outside.
At school, Joshua’s personal teacher Malika speaks to him frequently—asks questions, names objects,
and encourages verbal communication. Joshua frequently engages other children in play. Joshua’s
mother is impressed with how quickly he learns new words. His vocabulary is exploding. One of Joshua’s
favorite games to play with Malika is hide-and-seek. When he first joined Three Trees, as a 6-month-old
baby, Malika would hide objects right in front of him and Joshua wouldn’t even attempt to find them.
But at two years of age Joshua is eager to search every corner of the room to find them.
Recently Joshua has become a bit mischievous. One day while hiding he bumped up against a bookshelf
that was adorned with a potted plant. The potted plant fell and shattered on the ground. Now, Joshua
picks up different objects on countertops and purposefully drops them on the ground, interested in how
they fall and what happens when they hit the ground.
1. Evaluate Joshua’s child care setting. Specifically, what factors indicate its quality? What effects can
Joshua expect given his interactions at Three Threes Nursery School?
2. Provide examples of Joshua’s behavior that illustrate sensorimotor reasoning.
3. In what ways did his experiences at Three Trees influence Joshua’s language development? Why?
CHAPTER SUMMARY
5.1 Discuss the cognitive-developmental perspective on infant reasoning.
During the sensorimotor period, infants move through six substages that transition the infant from
strengthening basic reflexes to engaging in primary, secondary, and tertiary circular reactions and
demonstrating representational thought. Core knowledge researchers using violation of expectation and
other tasks have shown that young infants may have a grasp of the physical properties of objects, such
as object permanence, earlier than Piaget indicated.
5.2 Evaluate Piaget’s sensorimotor reasoning stage in light of research evidence.
Criticism of the sensorimotor reasoning stage tends to center around the method Piaget used to assess
infants’ abilities. Research that relies on infant looking rather than reaching behaviors, such as violationof-expectation tasks, suggested that object permanence develops earlier than Piaget believed. Findings
with A-not-B tasks and deferred imitation tasks also suggest that young infants’ thinking is more
advanced than Piaget theorized. Core knowledge theorists argue that infants are born with several
innate knowledge systems, or core domains of thought, that enable them to adapt to their world and
learn very quickly from birth.
5.3 Describe the information processing system and its development in infancy.
According to information processing theory, we are born with a functioning information processing
system comprised of sensory memory, working memory (which includes a short-term store, a processing
component, and the central executive), and long-term memory. Young infants require a long time to
habituate to stimuli and will look longer at stimuli than older infants. By 3 months of age infants can
remember a visual stimulus for 24 hours and for several days—or even weeks, by the end of the first
year of life. Infants’ earliest categories are based on the perceived similarity of objects. As early as 7
months of age, infants use conceptual categories based on perceived function and behavior. Seven- to
12-month-old infants use many categories to organize objects, such as food, furniture, birds, animals,
vehicles, kitchen utensils, and more. Twelve- to 30-month-old infants categorize objects first at a global
level and then at more specific levels.
5.4 Discuss individual differences in infant intelligence.
The most commonly used measure of infant intelligence is the BSID-III, or Bayley-III, appropriate for
infants from 2 months through 30 months of age. The intellectual abilities measured by the Bayley-III are
critical indicators of neurological health and are useful for charting developmental paths, diagnosing
neurological disorders, and detecting mental retardation very early in life but are not closely correlated
with childhood intelligence. New approaches look to information processing as an indicator of
intellectual skill.
5.5 Summarize the patterns of language development during infancy and toddlerhood.
Newborns are able to hear all of the sounds of which the human voice is capable, but their ability to
perceive nonnative speech sounds declines over the first year of life. Infants progress from cooing to
babbling and then first words. Infants learn words through fast mapping, but their own speech lags
behind what they can understand, and they display underextension and overextension errors. At about
21 months of age, most children compose their first simple two-word sentences, telegraphic speech.
Bilingual infants show similar patterns of language development.
5.6 Compare and contrast influences on language development.
An interactionist perspective integrates nature and nurture, noting that we have innate perceptual biases
for discriminating and listening to language, and the brain is wired for language at birth (from nativist
and evolutionary perspectives). At the same time, language acquisition occurs in a social context in
which adults use infant-directed speech to catch the infant’s attention and facilitate language
development by responding in ways that foster language learning, such as by using expansions and
recasts. Cultures differ in the use of infant-directed speech and the forms that parental responsiveness
takes, but both influence language development.
Key Terms
Accommodation
A-not-B error
Assimilation
Attention
Babbling
Broca’s area
Canonical babbling
Categorization
Central executive
Circular reaction
Cognitive-developmental perspective
Cognitive disequilibrium
Cognitive equilibrium
Cognitive schema
Cooing
Core knowledge theory
Deferred imitation
Executive function
Expansions
Fast mapping
Grammar
Holophrases
Infant-directed speech
Intelligence
Language acquisition device (LAD)
Long-term memory
Mental representation
Object permanence
Overextension
Primary circular reactions
Productive language
Recast
Receptive language
Recognition memory
Schemas
Secondary circular reactions
Sensory memory
Telegraphic speech
Tertiary circular reactions
Transfer deficit
Underextension
Universal grammar
Violation-of-expectation task
Vocabulary spurt
Wernicke’s area
Working memory
Descriptions of Images and Figures
Back to Figure
A child standing near a hairy cat. The thought bubble pointing to him reads “Kitty.” Below the picture is
the label “Assimilation.” On the right side of this image is the same child standing near a hairless cat. The
thought bubble pointing to the child has a question mark. On the right side of this picture is the same
child near the same hairless cat. The thought bubble above his head is labeled “Kitty!” The label below
these images reads “Kitty!”
Back to Figure
First row has two infant images of the second substage side by side. Two arched arrows, one above and
the other below are placed between the two images. The first row is marked on the left side as A and
the label below the left image reads “Baby brings hands together.” The label below the right image reads
“Baby enjoys it and does it again.” The middle row has two infant images of the substage 3 side by side.
Two arched arrows, one above and the other below are placed between the two images. The middle row
is marked on the left side as B and the label below the left image reads “Baby shakes rattle.” The label
below the right image reads “Baby enjoys rattling sound and does it again.” The bottom row has three
infant images of the fifth substage. Two arched arrows, one above and the other below are placed
between the left image and the middle image, and the middle image and the right image. Two other
arched arrows, one above and the other below are placed between the left image and the right image,
one through over and the other through below the middle image. The bottom row is marked on the left
side as C and the label below the left image reads “Baby hits pot with a spoon and enjoys the sound.”
The sound produced is marked as “Bang.” The label below the middle image reads “Baby repeats with
other objects and enjoys sound.” The label below the right image reads “Loud bang.”
Back to Figure
The figure has two parts, A and B.
In part A at the left, there are two rows depicting the side view of habituation and test displays. From top
to bottom the details of the rows are as follows:
Top row: It consists of a rectangular box labeled “Experimental condition,” which is divided vertically into
three. From left to right, they are labeled “Habituation,” “Impossible test,” and “Possible test.” The box
“Habituation” bears a screen placed horizontally, along with an arched arrow depicting the direction of
rotation through an angle of 180 degrees, up and away from the infant. “Impossible test” also bears a
screen placed horizontally along with an arched arrow depicting the direction of rotation through an
angle of 180 degrees, but in addition here there is a box placed vertically at the far edge of the screen.
“Possible test” bears a screen placed horizontally along with an arched arrow depicting the direction of
rotation up to where it contacts the box placed vertically, through an angle of rotation less than 180
degree.
Bottom row: It consists of a rectangular box labeled “Control condition,” which is divided vertically into
three. From left to right, they are labeled “Habituation,” “Full rotation test,” and “Partial rotation test.”
Here, the screen rotations of each are identical with its counterpart in the top row, but no box is
presented.
In part B at the right, the results of “Experimental condition” and “Control condition” are placed in the
top and bottom rows respectively. From top to bottom, the details of the rows are as follows:
Top row: The line graphs of “Experimental condition” is depicted in a single pane, partitioned into left
and right panels titled “Habituation” and “Test” respectively. The horizontal axis represents “Trial #,”
ranging from -6 to 4. The vertical axis represents “Looking Time(s)” ranging from 0 to 20, in increments
of 20. There are two line graphs in the right panel labeled as “Impossible” and “Possible.” The data from
the graphs are given in the table below. Values are approximate.
Experimental Condition
Habituation Test impossible
Trial
−6 56
−5 44
−4 42
−3 20
−2 10
−1 16
1
28
2
22
3
32
Test possible
18
19
18
Bottom row: The line graphs of “Control condition” is depicted in a single pane, partitioned into left and
right panels titled “Habituation” and “Test” respectively. The horizontal axis represents “Trial #,” ranging
from -6 to 4. The vertical axis represents “Looking Time(s)” ranging from 0 to 20, in increments of 20. The
line graphs in the right panel are further labeled as “Full” and “Partial.” The data from the graphs are
given in the table below. Values are approximate.
Control Condition
Habituation
Trial
−6 36
−5 50
−4 38
−3 20
−2 22
−1 18
1
2
3
4
Back to Figure
Test Full Test Partial
18
16
14
18
22
12
19
10
The figures are placed in two rows. The left figure of the top row depicts an infant sitting and observing
a ball being placed under a piece of cloth. The right figure depicts the infant pulling up the piece of
cloth to take the ball. The left figure of the bottom row depicts the ball being moved to and placed
below a piece of cloth on the other side of the infant. The right figure of the bottom row depicts the
infant pulling up the piece of cloth under which the ball was kept first. On the other side of the infant,
the ball is kept under a piece of cloth and the ball is bulging out from the cloth.
Back to Figure
A right arrow points from incoming information to sensory memory. A right arrow points from sensory
memory to working memory. A down arrow points from central executive to working memory. From
working memory a down arrow points to response. On the right side of working memory, encoding and
retrieval are written above and below. An arched up arrow points from working memory to encoding.
From encoding an arched down arrow points to long-term memory which is written on the right side,
between encoding and retrieval. An arched down arrow points from long-term memory to retrieval. An
arched left arrow points from retrieval to working memory.
Back to Figure
The horizontal axis represents the length of delay from 1 month to 12 month and vertical axis represents
the percentage of children demonstrating ordered recall. The vertical axis ranges from 0 to 100 with an
increment of 10. The graph plots the data for 13-, 16-, and 20-month-old infants. The data from the
graph is shown in the table below. Values are approximate.
Length of delay Percentage of children demonstrating ordered recall
13 months
16 months
20 months
1 month
79
93
100
3 month
68
93
100
6 month
40
71
81
9 month
41
50
79
12 month
39
61
68
Back to Figure
The horizontal axis represents “White,” “Black,” “Hispanic,” “Asian,” “American Indian,” and “Other.” The
vertical axis represents the percentage of children ranging from 0 to 80, in increments of 10. The graph
plots the data for “Low income,” “Poor,” and “Deep poverty.” The data from the graph is shown in the
table below:
Poor Families by Race/Ethnicity Percent (%)
Low income
White
28
Black
61
Hispanic
59
Asian
28
American Indian
60
Other
40
Back to Figure
Poor
12
34
28
12
35
19
Deep poverty
5
17
11
4
18
9
The horizontal axis for line graph A shows the time in months that start from 12 and end with 26 with an
increment of 2 and vertical axis labeled as words known that starts from 0 and end in 140 with an
increment of 20. The graph shows the number of words known for two children Jen and Anne. The line
graph shows Anne will know more words than Jen.
The horizontal axis for line graph B shows the time in months that start from 18 and end with 20.5 with
an increment of 0.5 and vertical axis labeled as words known that starts from 40 and end in 200 with an
increment of 20. The graph shows the number of words known for all children. The line graph shows the
words known for all children is in increasing order as time goes.
6 SOCIOEMOTIONAL DEVELOPMENT IN INFANCY AND
TODDLERHOOD
Halfpoint Images/Getty Images
As a newborn, Terrence expressed distress by spreading his arms, kicking his legs, and crying. When he
did this, his mother or father would scoop him up and hold him, trying to comfort him. Terrence began
to prefer interacting with attentive adults who cared for him. Soon, baby Terrence began to smile and
gurgle when held. In turn, Terrence’s parents played with him and were delighted to see his animated,
excited responses. As a toddler, his emerging language skills enabled Terrence to express his needs in
words. He quickly learned that words are powerful tools that can convey emotions (“I love you,
Mommy”). Without realizing it, Terrence began using words to help him manage strong emotions and
difficult situations. He learned to distract himself from stressful stimuli, like the neighbor’s scary dog, by
singing to himself. Terrence became able to express his ideas and feelings to everyone around him,
making for new and more complex relationships with his parents and siblings.
As Terrence illustrates, in the first two years of life, babies learn new ways of expressing their emotions.
They become capable of new and more complex emotions and develop a greater sense of selfunderstanding, social awareness, and self-management. These abilities influence their interactions with
others and their emerging social relationships. These processes collectively are referred to as
socioemotional development. In this chapter, we examine the processes of socioemotional development
in infancy and toddlerhood.
PSYCHOSOCIAL DEVELOPMENT IN INFANCY AND TODDLERHOOD
LEARNING OBJECTIVE
6.1 Summarize the psychosocial tasks of infancy and toddlerhood.
According to Erik Erikson (1950), as we travel through the lifespan we proceed through a series of
psychosocial crises, or developmental tasks. As discussed in Chapter 1, how well each crisis is resolved
influences psychological development and how the individual approaches the next crisis or
developmental task. Erikson believed that infants and toddlers progress through two psychosocial
p
p g
g
p y
stages that influence their personality development: trust versus mistrust and autonomy versus shame
and doubt.
Trust Versus Mistrust
From the day she was born, each time Carla cried, her mother or father would come to her bassinet and
hold her, check her diaper, and feed her if necessary. Soon, Carla developed the basic expectation that
her parents would meet her needs. According to Erikson (1950), developing a sense of trust versus
mistrust is the first developmental task of life. Infants must develop a view of the world as a safe place
where their basic needs will be met. Throughout the first year of life, infants depend on their caregivers
for food, warmth, and affection. If parents and caregivers attend to the infant’s physical and emotional
needs and consistently fulfill them, the infant will develop a basic sense of trust in her caregivers and, by
extension, in the world in general.
If caregivers are neglectful or inconsistent in meeting an infant's needs, the infant will develop a sense of
mistrust, feeling that they cannot count on others for love, affection, or the fulfillment of other basic
human needs. The sense of trust or mistrust developed in infancy influences how people approach the
subsequent stages of development. Specifically, when interaction with adults inspires trust and security,
babies are more likely to feel comfortable exploring the world, which enhances their learning, social
development, and emotional development (Gedge & Abell, 2020).
Autonomy Versus Shame and Doubt
Two-and-a-half-year-old Shane is an active child who vigorously explores his environment, tests new
toys, and attempts to learn about the world on his own. At dinnertime, he wants to feed himselfand gets
angry when his parents try to feed him. Each morning, Shane takes pleasure in attempting to dress
himself and expresses frustration when his mother helps. Shane is progressing through the second stage
in Erikson’s scheme of psychosocial development—autonomy versus shame and doubt—which is
concerned with establishing a sense of autonomy, or the feeling that one can make choices and direct
oneself.
Toddlers walk on their own, express their own ideas and needs, and become more independent. Their
developmental task is to learn to do things for themselves and feel confident in their ability to maneuver
in their environment. According to Erikson (1950), if parents encourage toddlers’ initiative and allow
them to explore, experiment, make mistakes, and test limits, toddlers will develop autonomy, selfreliance, self-control, and confidence. If parents are overprotective or disapprove of their toddlers’
struggle for independence, the children may begin to doubt their abilities to do things by themselves,
may feel ashamed of their desire for autonomy, may passively observe, and may not develop a sense of
independence and self-reliance.
Children take pride in completing self-care tasks, such as tooth brushing, all
by themselves, developing a sense of autonomy.
iStock/dszc
Both trust and autonomy develop out of warm and sensitive parenting and developmentally appropriate
expectations for exploration and behavioral control (Lewis & Abell, 2020). Without a secure sense of
trust in caregivers, toddlers will struggle to establish and maintain close relationships with others and
will find it challenging to develop autonomy. Much of the research on parenting examines mothers, but
fathers’ interactions with infants also support autonomy development (Hughes et al., 2018). Parenting
practices that promote the development of autonomy in infants and toddlers include explaining
problems in developmentally appropriate ways, teaching different ways of communicating empathy, and
modeling desired behaviors (Andreadakis et al., 2019). These practices also help infants and toddlers
internalize rules and learn how to regulate or direct their behavior (Meuwissen & Carlson, 2019).
Children who develop a sense of individuality and confidence in their own abilities to meet new
challenges are better equipped to interact with and adapt to the world around them.
Thinking in Context: Applied Developmental Science
1. What kinds of behaviors on the part of parents promote a sense of trust in infants? How would you
advise new parents who wish to help their infants develop trust?
2. Do trust-promoting activities, such as attentiveness and cuddling, also foster a sense of autonomy
in infants? Why or why not?
Thinking in Context: Lifespan Development
Families are immersed in contexts that differ in many ways: urban, suburban, or rural, with varying levels
of socioeconomic status, access to health resources, safety, and exposure to racism and discrimination.
1. How might these differences and parents’ experiences influence their interactions with infants
and their infants’ psychosocial development?
2. Would you expect infants in each of these contexts to demonstrate trust and autonomy in similar
ways? Why or why not?
EMOTIONAL DEVELOPMENT IN INFANCY AND TODDLERHOOD
LEARNING OBJECTIVE
6.2 Describe emotional development and the role of contextual influences on emotional
development in infants and toddlers.
What emotions do infants feel? Infants cannot describe their experiences and feelings, which makes
studying their emotional development quite challenging. Most people show their emotions on their
faces, such as by smiling or frowning. If we use facial expressions as a guide to what emotions infants
might feel, the first and most reliable emotion that newborns show is distress. They cry, wail, and flail
their arms and bodies, alerting caregivers to their need for attention. Newborns also show interest with
wide-eyed gazes when something catches their attention, and they smile when they are happy.
Infants’ Emotional Experience
Are we born with the ability to feel emotions? Newborns show facial expressions that are associated with
interest, distress, disgust, and happiness or contentment (Izard et al., 2010). Infants’ facial expressions are
remarkably similar to those of adults (Sullivan & Lewis, 2003), but we do not know whether internal
emotional states accompany their facial expressions. We cannot ask infants what they feel, so it is not
clear whether newborns experience the emotions that their faces show.
Even young infants exhibit a wide range of emotions. Observation of
newborn facial expressions suggests that newborns experience interest,
distress, disgust, and happiness or contentment. Between 2 and 7 months of
age, they begin to display other emotions, such as anger, sadness, surprise,
and fear.
mapodile/Getty Images
Basic Emotions
Basic emotions, also known as primary emotions (happiness, sadness, interest, surprise, fear, anger, and
disgust), are universal—experienced by people around the world (Cordaro et al., 2018; Lench et al.,
2018). Basic emotions emerge in all infants at about the same ages and are seen and interpreted
similarly in all cultures that have been studied, suggesting that they are inborn (Izard et al., 2010).
Between 2 and 7 months of age, infants begin to display anger, sadness, joy, surprise, and fear.
Research with adults suggests that emotions are the result of interactions among richly connected,
subcortical brain structures, including the brainstem and the limbic system, as well as parts of the
cerebral cortex (Celeghin et al., 2017; Kragel & LaBar, 2016). These structures develop prenatally and are
present in animals, suggesting that emotions serve a biological purpose, are crucial to survival, and are
likely experienced by infants (Rolls, 2017; Turner, 2014).
Table 6.1 Milestones in Emotional Development
Approximate Age Milestone
Birth
Basic emotions
Discriminates mother
2–3 months
Social smile
Distinguishes happiness, anger, surprise, and sadness
6–8 months
7–12 months
18–24 months
Fear, stranger anxiety, and separation protest occur
Social referencing
Self-conscious emotions appear. Develops vocabulary for talking about emotions
Emotions develop in predictable ways (Table 6.1). Although basic emotions are thought to be inborn, the
ways that they are expressed and the conditions that elicit them change during the first few months of
life. Newborns smile, and smiling is one of the most important emotional expressions in infancy.
Newborn smiles are reflexive, involuntary, and linked with shifts in arousal state (e.g., going from being
asleep to drowsy wakefulness), and they occur frequently during periods of rapid eye movement (REM)
sleep (Challamel et al., 2020; Kawakami et al., 2008). At about 3 weeks, infants smile while awake and
alert and in response to familiarity—familiar sounds, voices, and tastes (Sroufe & Waters, 1976).
During the second month of life, as infants’ vision improves, they smile more in response to visual stimuli
—sights that catch their attention, such as bright objects coming into view (Sroufe & Waters, 1976). The
social smile, which occurs in response to familiar people, emerges between 6 and 10 weeks of age and is
an important milestone in infant development because it shows social engagement (Messinger & Fogel,
2007). The social smile plays a large role in initiating and maintaining social interactions between infants
and adults, especially by enhancing caregiver–child bonding. Parents are enthralled when their baby
shows delight in seeing them, and the parents’ happy response encourages their baby to smile even
more (Beebe et al., 2016).
As infants grow, laughs begin to accompany their smiles, and they laugh more often and at more things.
Infants may show clear expressions of joy, intense happiness, as early as 2½ months of age while playing
with a parent and at 3 to 4 months of age in response to stimuli that they find highly arousing
(Messinger et al., 2019). At 6 months of age, an infant might laugh at unusual sounds or sights, such as
when Mommy puts a bowl on her head or makes a funny face. Laughing at unusual events illustrates the
baby’s increasing cognitive competence as he or she knows what to expect and is surprised when
something unexpected occurs. By 1 year of age infants can smile deliberately to engage an adult.
Smiling is one of the most important emotional expressions in infancy
because it plays a role in initiating and maintaining social interactions
between infants and adults.
iStock/quavondo
Negative emotions change over time as well. Distress is evident at birth when newborns experience the
discomfort of hunger, a heel prick, or a chilly temperature. Anger appears at about 6 months of age and
develops rapidly, becoming more complex in terms of elicitors and responses (Dollar & Calkins, 2019).
Initially, physical restrictions such as being restrained in a high chair or when being dressed can elicit
anger. The inability to carry out a desired action, such as unsuccessfully reaching to obtain a desired toy,
can also provoke frustration and anger. Between 8 and 20 months of age, infants gradually become
more reactive, and anger is more easily aroused (Braungart-Rieker et al., 2010). They become aware of
the actions of others, so that anger can be elicited by others’ behavior. For example, an infant may
become upset when Mommy goes to the door to leave, or when Grandma takes out the towels in
preparation for bath time. During the second year of life, temper tantrums become common when the
toddler’s attempts at autonomy are thwarted and he or she experiences frustration or stress. The anger
escalates with the child’s stress level (Potegal et al., 2007). Some toddlers show extreme tantrums, lie on
the floor, scream, and jerk their arms and legs. Other children’s tantrums are more subtle. They may
whine, mope, and stick out their lower lip. Similar to adults, infants’ emotional expressions are tied to
their own experiences and infants display emotional responses to stimuli that are unique to them
(Camras, 2019).
Self-Conscious Emotions
Emotional development is an orderly process in which complex emotions build on the foundation of
simple emotions. The development of self-conscious emotions, or secondary emotions—such as
empathy, pride, embarrassment, shame, and guilt—depends on cognitive development, as well as an
awareness of self. Self-conscious emotions do not begin to emerge until about 15 to 18 months, and
they largely develop during the second and third years of life (Lewis, 2019). In order to experience selfconscious emotions, toddlers must be able to have a sense of self, observe themselves and others, be
aware of standards and rules, and compare their behavior with those standards (Lewis, 2016). Feelings of
pride arise from accomplishing a personally meaningful goal, whereas guilt derives from realizing that
one has violated a standard of conduct. Parental evaluations are the initial basis for many secondary
emotions (Goodvin et al., 2015).
Emotion Regulation
As children become aware of social standards and rules, emotion regulation—the ability to control their
emotions—becomes important. How do infants regulate emotions? During the first 2 to 3 months of life,
infants manage negative emotions by sucking vigorously on their hands or objects. At about 3 months
of age infants start to use voluntary motor behaviors, such as turning their bodies away from distressing
stimuli (Baker, 2018).
Smiling is also thought to serve a purpose in regulating emotions, as it allows infants to control aspects
of a situation without losing touch with it. When infants get excited and smile, they often look away
briefly. This involuntary behavior may be a way of breaking themselves away from the stimulus and
allowing them to regroup, preventing overstimulation. Smiling is associated with a decline in heart rate,
suggesting that it is a relaxation response to decrease infants’ level of arousal.
Whereas 6-month-old infants are more likely to use gaze aversion and fussing as primary emotion
regulatory strategies, 12-month-old infants are more likely to use self-soothing (e.g., thumb sucking,
rocking themselves) and distraction (chewing on objects, playing with toys). Responsive caregiving that
acts on behalf of children’s responses, helping them orient or move toward or away from overwhelming
stimuli, can help infants and toddlers regulate their emotions (Stifter & Augustine, 2019). With advances
in cognition and motor control, the infant can explore the environment by walking, initiate social
interactions, and remember past experiences (Baker, 2018). By 18 months of age, toddlers actively
attempt to change the distressing situation, such as by moving away from upsetting stimuli, and they
begin to use distraction, such as by playing with toys or talking (Crockenberg & Leerkes, 2004; Feldman
et al., 2011). The caregiving environment plays a large role in infants’ and toddlers’ emerging abilities to
engage in self-regulation. Warm and supportive interactions with parents and other caregivers can help
infants understand their emotions and learn how to manage them.
Social Interaction and Emotional Development
Infants and young children often need outside assistance in regulating their emotions. Interactions with
parents and caregivers help infants understand and learn to manage their emotions.
Sensitive Caregiving
Caregivers help infants regulate their emotions by using soothing behaviors and minimizing their
exposure to overwhelming stimuli. Sensitive responses coupled with soft vocalizations aid 3-month-old
infants in regulating distress (Spinelli & Mesman, 2018). Sensitive caregivers respond to infants’
emotional reactions and try to satisfy their needs, attempt to elicit positive responses and minimize
negative ones, and seek to maintain an optimal level of arousal (stimulating but not overwhelming) in
their infant (Baker, 2018). When mothers responded promptly to their 2-month-old infants’ cries, these
same infants, at 4 months of age, cried for shorter durations, were better able to manage their emotions,
and stopped crying more quickly than other infants (Jahromi & Stifter, 2007). Caregiver sensitivity
predicts self-regulation in infancy into middle childhood (Morawska et al., 2019). Responsive parenting
that is attuned to infants’ needs helps infants develop skills in emotion regulation, especially in
managing negative emotions like anxiety, as well as their physiological correlates, such as accelerated
heart rate (Feldman et al., 2011).
Parents help their infants learn to manage emotions through a variety of strategies, including direct
intervention, modeling, selective reinforcement, control of the environment, verbal instruction, and
touch (Stifter & Augustine, 2019; Waters et al., 2017). These strategies change as the infants grow older.
Touching becomes a less common regulatory strategy with age, whereas vocalizing and distracting
techniques increase (Meléndez, 2005). When mothers provide guidance in helping infants regulate their
emotions, the infants tend to engage in distraction and mother-oriented strategies, such as seeking
help, during frustrating events (Thomas et al., 2017). Parents who model emotion regulation strategies,
such as using distraction, are more likely to have toddlers who use those strategies to soothe themselves
in stressful situations (Schoppmann et al., 2019).
Parent–Infant Interaction
Parent–infant interactions undergo continuous transformations as infants develop. Infants’ growing
motor skills influence their interactions with parents, as well as their socioemotional development.
Crawling, creeping, and walking introduce new challenges to parent–infant interaction and
socioemotional growth (Adolph & Franchak, 2017). As crawling begins, parents and caregivers respond
with happiness and pride, positive emotions that encourage infants’ exploration. As infants gain motor
competence, they wander further from their parents (Thurman & Corbetta, 2017). Crawling increases a
toddler’s capability to attain goals—a capability that, while often satisfying to the toddler, may involve
hazards.
As infants become more mobile, emotional outbursts become more common. Parents report that
advances in locomotion are accompanied by increased frustration as toddlers attempt to move in ways
that often exceed their abilities or are not permitted by parents (Clearfield, 2011; Pemberton Roben et
al., 2012). When mothers recognize the dangers posed to toddlers by objects such as houseplants, vases,
and electrical appliances, they sharply increase their expressions of anger and fear, often leading to fear
and frustration in their toddlers. At this stage, parents actively monitor toddlers’ whereabouts, protect
them from dangerous situations, and expect them to comply—a dynamic that is often a struggle,
amounting to a test of wills. At the same time, these struggles help the child to begin to develop a grasp
of mental states in others that are different from his or her own.
Responsive parenting helps infants learn to manage their emotions and selfregulate.
iStock/AleksandarNakic
Changes in emotional expression and regulation are dynamic, because the changing child influences the
changing parent. In particular, mothers and infants systematically influence and regulate each other’s
emotions and behaviors. Mothers regulate infant emotional states by interpreting their emotional
signals, providing appropriate arousal, and reciprocating and reinforcing infant reactions. Infants
regulate their mother’s emotions through their receptivity to her initiations and stimulation, and by
responding to her emotions (Bornstein et al., 2011, 2012). By experiencing a range of emotional
interactions—times when their emotions mirror those of their caregivers and times when their emotions
are different from those of their caregivers—infants learn how to transform negative emotions into
neutral or positive emotions and regulate their own emotional states (Guo et al., 2015).
Social Referencing
Early in life, infants become able to discriminate facial expressions that indicate emotion. In one study, 2day-old infants initially did not show a preference for a happy or disgusted face, but after being
habituated to either a happy or disgusted face they successfully discriminated between the two,
suggesting an early sensitivity to dynamic faces expressing emotions (Addabbo et al., 2018). Likewise,
newborns are able to discriminate happy faces from fearful ones (Farroni et al., 2007). It is thought that
infants are innately prepared to attend to facial displays of emotion, because such displays are
biologically significant and the ability to recognize them is important for human survival (Leppanen,
2011). Between 2 and 4 months of age, infants can distinguish emotional expressions including
happiness as opposed to anger, surprise, and sadness (Bornstein et al., 2013). Six-and-one-half-monthold infants can identify and match happy, angry, and sad emotions portrayed on faces, but also body
movements indicating emotion (Hock et al., 2017).
Beyond recognizing the emotional expressions of others, infants also respond to them. Between 6 and
10 months of age, infants begin to use social referencing, looking to caregivers’ or other adults’
emotional expressions to find clues for how to interpret and respond to ambiguous events (Ruba &
Repacholi, 2019; Walle et al., 2017). Social referencing influences infants’ emotional reactions and,
ultimately, behavior. When toddlers grab the sofa to pull themselves up, turn, and then tumble over as
they take a step, they look to their caregivers to determine how to interpret their fall. If caregivers
respond with fearful facial expressions, infants are likely to also be fearful, but if caregivers instead smile,
infants will probably remain calm and return to their attempts at walking. The use of social referencing is
one way that infants demonstrate their understanding that others experience emotions and thoughts.
Older infants tend to show a negativity bias when it comes to social referencing. That is, they attend to
and follow social referencing cues more closely when the cues indicate negative attitudes toward an
object, compared with neutral or happy attitudes (Vaish et al., 2008). Infants’ behavior may be more
influenced by the emotional message conveyed in the vocal information than the facial expressions
themselves, especially within the context of fearful messages (Biro et al., 2014; Ruba & Repacholi, 2019).
How infants employ social referencing changes with development. Ten-month-old infants show selective
social referencing. They monitor the caregiver’s attention and do not engage in social referencing when
the adult is not attending or engaged (Stenberg, 2017). At 12 months, infants use referential cues such
as the caregiver’s body posture, gaze, and voice direction to determine to what objects caregivers’
emotional responses refer (Brooks & Meltzoff, 2008). Twelve-month-old infants are more likely to use a
caregiver’s cues as guides in ambivalent situations when the caregiver responds promptly to the infant's
behavior (Stenberg, 2017). Social referencing reflects infants’ growing understanding of the emotional
states of others; it signifies that infants can observe, interpret, and use emotional information from
others to form their own interpretation and response to events.
Exposure to Early Life Stress
Many infants live in stressful contexts and are exposed to adversity, including maltreatment, poverty, and
violence. Very young infants likely do not recall specific experiences and events, but early exposure to
trauma may affect infants’ development in ways that can last a lifetime. Whereas maladaptive contexts
may pose risks of physical harm to children, with negative influences on brain development, trauma
poses invisible long-term risks to children’s emotional development and mental health (Juruena et al.,
2020; Mueller & Tronick, 2019).
Early trauma may exert a biological effect on emotional development. The experience of early social
adversity may have epigenetic effects on the genes that regulate the endocrine system, which controls
hormone production and release at all ages in life (Agorastos et al., 2019; Conradt, 2017). Infancy may be
a particularly plastic time in development, with heightened potential for epigenetic changes that may
sensitize individuals’ responses to stress throughout a lifetime (Laurent et al., 2016).
Experiencing adversity early in life may have epigenetic effects on the genes
that regulate responses to stress. The caregiving environment also influences
the developing stress response system and can buffer the negative effects of
trauma.
Reuters/Alamy Stock Photo
However, not all infants respond to early life stress with heightened reactivity. Some infants exposed to
trauma show lower levels of stress hormones and reduced reactivity to stress (Turecki & Meaney, 2016).
The timing and intensity of adversity influence developmental outcomes. Exposure to particularly
intense chronic stress early in development can lead to hyperactive stress responses that may be
followed by blunted responses (Laurent et al., 2016). Blunted responses may reflect adaptations to
chronically stressful situations. Unpredictable stressors, on the other hand, may lead to heightened stress
reactivity as the individual adapts to volatile and unexpected situations (Blair, 2010). Both heightened
and blunted stress responses may be adaptive attempts to optimize survival in nonoptimal caregiving
environments, yet these adaptations may carry behavioral costs, such as heightened distress when
confronted with stress and longer-term anxiety and depressive symptoms, which negatively affect
developmental trajectories (Laurent et al., 2016).
Early life stress poses risks to emotional development, but the caregiving environment also influences
the developing stress response system. Mothers buffer and regulate infants’ hormonal and behavioral
responses to threats (Howell et al., 2017). Sensitive mothers tend to have infants who display better selfregulation during stressful events; intrusive mothers tend to have the opposite effect (Enlow et al., 2014).
Sensitive caregiving can reduce the negative epigenetic effects of early life stress (Janusek et al., 2019;
Provenzi et al., 2020). Warm parenting within a predictable stimulating environment with supportive
adults and family can help infants develop the self-regulation skills to adapt to adverse contexts.
Unfortunately, trauma often disrupts the caregiving system, making adaptation quite difficult.
Cultural Influences on Emotional Development
As we have already seen, emotional development does not occur in a vacuum. Contextual factors,
including culture, influence how infants interpret and express emotions, as well as what emotions they
feel.
Caregiver Responsiveness
Cultures often have particular beliefs about how much responsiveness is appropriate when babies cry
and fuss, as well as expectations about infants’ abilities to regulate their own emotions (Halberstadt &
Lozada, 2011). The !Kung hunter-gatherers of Botswana, Africa, respond to babies’ cries nearly
immediately (within 10 seconds), whereas Western mothers tend to wait a considerably longer period of
time before responding to infants’ cries (e.g., 10 minutes) (Barr et al., 1991). Fijian mothers tend to be
more responsive than U.S. mothers to negative facial expressions in their infants (Broesch et al., 2016).
Gusii mothers believe that constant holding, feeding, and physical care are essential for keeping an
infant calm, which in turn protects the infant from harm and disease; therefore, like !Kung mothers, Gusii
mothers respond immediately to their babies’ cries (LeVine et al., 1994). Infants from non-Western
cultures are thought to cry very little because they are carried often (Bleah & Ellett, 2010). In one study,
infants born to parents who were recent immigrants from Africa cried less than U.S. infants, illustrating
the role of culture in influencing infant cries (Bleah & Ellett, 2010).
Caregivers’ responses to infant cries influence infants’ capacity for self-regulation and responses to
stress. Babies who receive more responsive and immediate caregiving when distressed show lower rates
of persistent crying, spend more time in happy and calm states, and cry less overall as they approach
their first birthday (Axia & Weisner, 2002; Papoušek & Papoušek, 1990). Yet, the form that
responsiveness takes can vary with culture and socialization goals.
Emotional Socialization
Every society has a set of emotional display rules that specify the circumstances under which various
emotions should or should not be expressed (Safdar et al., 2009). We are socialized to learn and enact
these rules very early in life through interactions with others. Interactions among parents and infants are
shaped by the culture in which they live, which, in turn, influences the emotional expressions they share
and display (Bornstein et al., 2013).
Western cultures tend to emphasize autonomy and independence. Parents in these cultures tend to
encourage emotional expression in their children, often through modeling. When North American
mothers play with their 7-month-old babies, for instance, they tend to model positive emotions,
restricting their own emotional displays to show joy, interest, and surprise (Malatesta & Haviland, 1982).
They also are more attentive to infants’ expression of positive emotions, such as interest or surprise, and
respond less to negative emotions (Broesch et al., 2016). Italian mothers tend to welcome and
encourage infants’ self-expressive smiles and coos (Bornstein et al., 2012). Through early interactions
with caregivers, children learn about situations that elicit emotions and how to regulate emotions (Yang
& Wang, 2019).
East Asian cultures tend to deemphasize emotional expression, viewing it as disruptive to group
harmony. Parents in these cultures tend to express emotion less frequently. Thus, babies are socialized to
respond and display their emotions in culturally acceptable ways. Parents’ cultural orientation influences
their emotional expressivity. In one study, Chinese immigrant parents’ emotional expressivity was related
to their cultural orientation (Chen et al., 2015). Parents who were positively oriented toward American
culture tended to show more emotional expression whereas those who were oriented more toward
Chinese culture tended to be less emotionally expressive. Similar observations of emotional expressivity
of mothers and their 4-month-old infants during face-to-face interactions showed European American
mothers spent more time displaying positive affect and less time expressing neutral or negative affect
than did Chinese mothers who recently immigrated to the United States (Liu et al., 2013). Mothers’
cultural orientation influenced their interactions. Second-generation Chinese immigrant mothers or
those who had immigrated more than 10 years ago showed similar patterns of emotional expressivity as
European American mothers (Liu et al., 2013).
In some cultures, infants cry very little, perhaps because they are in constant
contact with their mothers.
VW Pics/Contributor/Getty Images
Which emotions are considered acceptable, as well as how they should be expressed, differ by culture
and context (Yang & Wang, 2019). Whereas North American parents tickle and stimulate their babies,
encouraging squeals of pleasure, the Gusii and Aka people of Central Africa prefer to keep babies calm
and quiet. They engage in little face-to-face play and look away as infants display peaks of positive
emotion (Hewlett et al., 1998; LeVine et al., 1994). Cameroonian Nso parents, members of a rural farming
culture, expect calmness from children (Keller & Otto, 2009). Infants’ emotional expressions are not
reciprocated by adults, and Cameroonian Nso infants soon learn to display calm, sober faces. Although
at surface glance it might appear as if Nso adults ignore their infants’ emotional expressions, that is not
the case. Instead, Nso parents and infants display a different path toward emotional expression and
emotional regulation than Western infants (Lavelli et al., 2019). Nso infants are often in body contact
with their mothers and their emotional expressions are monitored more by maternal body attention
than visual attention (Keller, 2019). It is through these patterns of body contact that Nso infants
experience interactional warmth and learn emotional regulation, as compared with the visual
interactions that characterize Western infant–parent dyads
The specific emotional display rules that infants learn, whether to express or restrain strong positive and
negative emotions, varies with culture. Cultures also specify the conditions under which emotions should
be shown and the stimuli that should evoke emotion, as discussed next.
Stranger Wariness
stranger anxiety
Many infants around the world display stranger wariness (also known as
), a fear of
unfamiliar people. In many, but not all cultures, stranger wariness emerges at about 6 months and
increases throughout the first year of life, beginning to decrease after about 15 months of age
(Bornstein et al., 2013; Sroufe, 1977). Locomotion, infant success in crawling or walking, tends to precede
the emergence of stranger wariness, suggesting interconnections among motor and emotional
development (Brand et al., 2020). From an evolutionary perspective, stranger wariness may have
emerged to protect infants as they became able to initiate new interactions with unknown and
potentially unsafe adults (Hahn-Holbrook et al., 2010).
Whether infants show stranger wariness depends on the infants’ overall temperament, their past
experience, and the situation in which they meet a stranger (Thompson & Limber, 1991). The pattern of
stranger wariness varies among infants. Some show rapid increases and others show slow increases in
stranger wariness; once wariness has been established, some infants show steady decline and others
show more rapid changes. Twin studies suggest that these patterns are influenced by genetics, because
the patterns of change are more similar among monozygotic twins (identical twins who share 100% of
their genes) than dizygotic twins (fraternal twins who share 50% of their genes) (Brooker et al., 2013).
Among North American infants, stranger wariness is generally expected by parents and caregivers.
However, infants of the Efe people of Zaire, Africa, show little stranger wariness. This is likely related to
the Efe collective caregiving system, in which Efe babies are passed from one adult to another, relatives
and nonrelatives alike (Tronick et al., 1992), and the infants form relationships with the many people who
care for them (Meehan & Hawks, 2013). In contrast, babies reared in Israeli kibbutzim (cooperative
agricultural settlements that tend to be isolated and subjected to terrorist attacks), tend to demonstrate
widespread wariness of strangers. By the end of the first year, when infants look to others for cues about
how to respond emotionally, kibbutz babies display far greater anxiety than babies reared in Israeli cities
(Saarni et al., 1998). In this way, stranger wariness may be adaptive, modifying infants’ drive to explore in
light of contextual circumstances (Easterbrooks et al., 2012).
As attachments form, infants become more wary and display stranger anxiety
when in the presence of unfamiliar people. In many, but not all cultures,
stranger wariness emerges at about 6 months and increases throughout the
first year of life.
Yoshikazu Tsuno/AFP/Getty Images
Stranger wariness illustrates the dynamic interactions betweenthe individual and context (LoBue &
Adolph, 2019). Infant’s emotionality and temperamental style, tendencies toward social interaction, and,
of course, past experience with strangers are important. Parental expectations and anxiety also matter.
Infants whose mothers report greater stress reactivity, who experience more anxiety and negative affect
in response to stress, show higher rates of stranger wariness (Brooker et al., 2013; Waters et al., 2014).
Characteristics of the stranger (e.g., his or her height), the familiarity of the setting, and how quickly the
stranger approaches influence how the infant appraises the situation (LoBue et al., 2019). Infants are
more open when the stranger is sensitive to the infant’s signals and approaches at the infant’s pace
(Mangelsdorf, 1992). Not all infants show stranger wariness. Instead, whether, how, and how long infants
demonstrate emergence of stranger wariness is the result of the complex interplay among individual
characteristics, experiences, and context (LoBue & Adolph, 2019).
Over the first few months of life, infants display the full range of basic emotions. As their cognitive and
social capabilities develop, they can experience complex social emotions, such as embarrassment. The
social world plays a role in emotional development. Adults interact with infants, provide opportunities to
observe and practice emotional expressions, and assist in regulating emotions. Much of emotional
development is the result of the interplay of infants’ emerging capacities and the contexts in which they
are raised.
Thinking in Context: Lifespan Development
1. Identify examples of how infants’ emotional development is influenced by their interactions
within their social and cultural contexts. Identify two examples of factors or experiences that
promote healthy emotional development and one that might hinder emotional development.
Explain your choices.
2. How might social referencing and stranger wariness reflect adaptative responses to a particular
context? Why does stranger wariness vary among children and cultures?
3. In what ways might emotional display rules, such as those regarding the display of positive and
negative emotions, illustrate adaptive responses to a particular context? Consider the context in
which you were raised. What emotional displays do you think are most adaptive for infants?
TEMPERAMENT IN INFANCY AND TODDLERHOOD
LEARNING OBJECTIVE
6.3 Discuss the styles and stability of temperament, including the role of goodness of fit in infant
development.
“Joshua is such an easygoing baby!” gushed his babysitter. “He eats everything, barely cries, and falls
asleep without a fuss. I wish all my babies were like him.” The babysitter is referring to Joshua’s
temperament. Temperament, the characteristic way in which an individual approaches and reacts to
people and situations, is thought to be one of the basic building blocks of emotion and personality
(Strelau, 2020). Temperament has strong biological determinants; behavior genetics research has shown
genetic bases for temperament (Saudino & Micalizzi, 2015). Yet the expression of temperament reflects
reciprocal interactions among genetic predispositions, maturation, and experience (Goodvin et al., 2015;
). Every infant behaves in a characteristic, predictable style that is influenced by his or her inborn
tendencies toward arousal and stimulation, as well as by experiences with adults and contexts (Planalp &
Goldsmith, 2020). In other words, every infant displays a particular temperament style.
Styles of Temperament
Begun in 1956, the New York Longitudinal Study is a pioneering study of temperament that followed 133
infants into adulthood. Early in life, the infants in the study demonstrated differences in nine
characteristics that are thought to capture the essence of temperament (Buss & Plomin, 1984; Chess &
Thomas, 1991; Goldsmith et al., 1987).
Activity level. Some babies wriggle, kick their legs, wave their arms, and move around a great deal,
whereas other babies tend to be more still and stay in one place.
Rhythmicity. Some infants are predictable in their patterns of eating, sleeping, and defecating; other
babies are not predictable.
Approach-withdrawal. Some babies tend to approach new situations, people, and objects, whereas
others withdraw from novelty.
Adaptability. Some babies get used to new experiences and situations quickly; others do not.
Intensity of reaction. Some babies have very extreme reactions, giggling exuberantly and crying with
piercing wails. Other babies show more subdued reactions, such as simple smiles and soft,
whimpering cries.
p
g
Threshold of responsiveness. Some babies notice many types of stimuli—sights, sounds, and touch
sensations—and react to them. Other infants notice few types of stimuli and seem oblivious to
changes.
Quality of mood. Some babies tend toward near-constant happiness while others tend toward
irritability.
Distractibility. Some babies can be easily distracted from objects or situations while others cannot.
Attention span. Some babies play with one toy for a long time without becoming bored, whereas
others get bored easily.
Some aspects of infant temperament, particularly activity level, irritability, attention, and sociability or
approach-withdrawal, show stability for months and years at a time and in some cases even into
adulthood (Lemery-Chalfant et al., 2013; Papageorgiou et al., 2014). Infants’ growing ability to regulate
their attention and emotions holds implications for some components of temperament, such as
rhythmicity, distractibility, and intensity of reaction. The components of infant temperament cluster into
three profiles (Thomas & Chess, 1977; Thomas et al., 1970):
Easy temperament: Easy babies are often in a positive mood, even-tempered, open, adaptable,
regular, and predictable in biological functioning. They establish regular feeding and sleeping
schedules easily.
Difficult temperament: Difficult babies are active, irritable, and irregular in biological rhythms. They
are slow to adapt to changes in routine or new situations, show intense and frequent unpleasant
moods, react vigorously to change, and have trouble adjusting to new routines.
Slow-to-warm-up temperament: Just as it sounds, slow-to-warm-up babies tend to be inactive,
moody, and slow to adapt to new situations and people. They react to new situations with mild
irritability but adjust more quickly than do infants with difficult temperaments.
Although it may seem as if all babies could be easily classified, about one-third of the infants in the New
York Longitudinal Study did not fit squarely into any of the three categories but displayed a mix of
characteristics, such as eating and sleeping regularly but being slow to warm up to new situations
(Thomas & Chess, 1977; Thomas et al., 1970).
Another influential model of temperament, by Mary Rothbart, includes three dimensions (Rothbart,
2011a; Rothbart & Bates, 2007):
Extraversion/surgency—the tendency toward positive emotions. Infants who are high in
extraversion/surgency approach experiences with confidence, energy, and positivity, as indicated by
smiles, laughter, and approach-oriented behaviors.
Negative affectivity—the tendency toward negative emotions, such as sadness, fear, distress, and
irritability.
Effortful control—the ability to focus attention, shift attention, and inhibit responses in order to
manage arousal. Infants who are high in effortful control are able to regulate their arousal and
soothe themselves.
From this perspective, temperament reflects how easily we become emotionally aroused or our reactivity
to stimuli, as well as how well we are able to control our emotional arousal (Rothbart, 2011). Some
infants and children are better able to distract themselves, focus their attention, and inhibit impulses
than others. The ability to self-regulate and manage emotions and impulses is associated with positive
long-term adjustment, including academic achievement, social competence, and resistance to stress, in
both Chinese and North American samples (Chen & Schmidt, 2015). Generally speaking, a difficult
temperament poses risks to adjustment (MacNeill & Pérez‐Edgar, 2020). Preterm infants are
predisposed to experience difficult temperaments as they tend to show greater arousal, difficulty
focusing their attention, and trouble regulating their arousal than full-term infants (Cassiano et al., 2020;
Reyes et al., 2019).
Infant temperament tends to be stable over the first year of life but less so than childhood
temperament, which can show stability over years, even into adulthood (Bornstein et al., 2019; Strelau,
2020). In infancy, temperament is especially open to environmental influences, such as interactions with
others (Bornstein et al., 2015; Gartstein et al., 2016). Young infants’ temperament can change with
experience, neural development, and sensitive caregiving (e.g., helping babies regulate their negative
emotions) (Jonas et al., 2015; Thompson et al., 2013). As infants gain experience and learn how to
regulate their states and emotions, those who are cranky and difficult may become less so. By the
second year of life, styles of responding to situations and people are better established, and
temperament becomes more stable. Temperament at age 3 remains stable, predicting temperament at
age 6 and personality traits at age 26 (Dyson et al., 2015).
Context and Goodness of Fit
Like all aspects of development, temperament is influenced by reciprocal reactions among individuals
and their contexts. An important influence on socioemotional development is the goodness of fit
between the child’s temperament and the environment around him or her, especially the parents’
temperaments and childrearing methods (Chess & Thomas, 1991).
The specific behaviors that comprise adaptive parenting vary with the infants’ temperament (MacNeill &
Pérez‐Edgar, 2020). Infants are at particular risk for poor outcomes when their temperaments show
poor goodness of fit to the settings in which they live (Rothbart & Bates, 1998). If an infant who is fussy,
difficult, and slow to adapt to new situations is raised by a patient and sensitive caregiver who provides
time for him or her to adapt to new routines, the infant may become less cranky and more flexible over
time. The infant may adapt her temperament style to match her context so that later in childhood she
may no longer be classified as difficult and no longer display behavioral problems (Bates et al., 1998). If,
on the other hand, a child with a difficult temperament is reared by a parent who is insensitive, coercive,
and difficult in temperament, the child may not learn how to regulate her emotions and may have
behavioral problems and adjustment difficulties that worsen with age, even into early adolescence and
beyond (Pluess et al., 2010). When children are placed in low-quality caregiving environments, those
with difficult temperaments respond more negatively and show more behavior problems than do those
with easy temperaments (Poehlmann et al., 2011).
Infant temperament both is influenced by and influences the bond with caregivers (Le Bas et al., 2020).
Goodness of fit at 4 and 8 months of age predicts a close bond with caregivers at 15 months (Seifer et
al., 2014; Takács et al., 2020). An infant’s temperament tends to be stable over time because certain
temperamental qualities evoke certain reactions from others, promoting goodness of fit. Easy babies
usually get the most positive reactions from others, whereas babies with a difficult temperament receive
mixed reactions (Chess & Thomas, 1991). An easy baby tends to smile often, eliciting smiles and positive
interactions from others, including parents, which in turn reinforce the baby’s easy temperamental
qualities (Planalp et al., 2017; Wittig & Rodriguez, 2019). Conversely, a difficult baby may evoke more
frustration and negativity from caregivers as they try unsuccessfully to soothe the baby’s fussing.
Mothers who view their 6-month-old infants as difficult may be less emotionally available to them (Kim
& Teti, 2014). Babies’ emotionality and negative emotions predict their mothers’ perception of parenting
stress and poor parenting behaviors (Oddi et al., 2013; Paulussen-Hoogeboom et al., 2007). Mothers of
difficult infants may question their own parenting competence (Takács et al., 2019).
Temperament can also be related to mothers’ own temperament, as well as their expectations about
their infants and their ability to parent (Grady & Karraker, 2017). In one study, mothers who,
, considered themselves less well equipped to care for their infants were found to be more
likely to have infants who showed negative aspects of temperament, such as fussiness, irritability, and
difficulty being soothed (Verhage et al., 2013). This suggests that perceptions of parenting may shape
views of infant temperament—and thereby shape temperament itself. In other research, three months
after giving birth, new mothers’ feelings of competence were positively associated with infant
temperament. Mothers’ beliefs about their ability to nurture are shaped by the interaction between their
infants’ traits and their own parenting self-efficacy, as well as their opportunities for developing
successful caregiving routines (Verhage et al., 2013). This contextual dynamic has been found to hold
true across cultures. Both British and Pakistani mothers in the United Kingdom reported fewer problems
with their infants’ temperaments at 6 months of age when the mothers had a greater sense of parenting
efficacy and displayed more warm and less hostile parenting styles (Prady et al., 2014).
giving birth
prior to
Socioemotional development is a dynamic process in which infants’ behavior and temperament styles
influence the family processes that shape their development. Sensitive and patient caregiving is not
always easy with a challenging child, and adults’ own temperamental styles influence their caregiving. A
poor fit between the caregiver’s and infant’s temperament can make an infant fussier and crankier.
When a difficult infant is paired with a parent with a similar temperament—one who is impatient,
irritable, and forceful—behavioral problems in childhood and adolescence are likely (Rubin et al., 1998;
Strelau, 2020).
Cultural Differences in Temperament
Researchers have observed consistent cultural differences in temperament that are rooted in cultural
norms for how individuals are perceived. Japanese mothers view their infants as interdependent beings
who must learn the importance of relationships and connections with others (Rothbaum et al., 2000).
North American mothers, on the other hand, view their task as shaping babies into autonomous beings
(Kojima, 1986). Whereas Japanese mothers tend to interact with their babies in soothing ways,
discouraging strong emotions, North American mothers are active and stimulating (Rothbaum et al.,
2000). Differences in temperament result, such that Japanese infants tend to be more passive, less
irritable and vocal, and more easily soothed when upset than North American infants (Kojima, 1986;
Lewis et al., 1993; Rothbaum et al., 2000). Culture influences the behaviors that parents view as desirable
and the means that parents use to socialize their infants (Chen & Schmidt, 2015; Kagan, 2013). Culture,
therefore, plays a role in how emotional development—in this case, temperament—unfolds.
Asian cultures often prioritize low arousal and emotionality and socialize infants in line with these values.
Chinese American, Japanese American, and Hmong children tend to display lower levels of irritability,
less physical activity, but also lower levels of positive emotions, and they engage in more self-quieting
and self-control than do European American children (Friedlmeier et al., 2015; Slobodskaya et al., 2013;
Super & Harkness, 2010). Similarly, a recent comparison of toddlers from Chile, South Korea, Poland, and
the United States showed that the South Korean toddlers scored highest on measures of control,
combined with low levels of activity (Krassner et al., 2017).
If infants from Asian cultures engage in more self-soothing, are they more temperamentally resistant to
stress? One study examined levels of the hormone cortisol in infants receiving an inoculation (Lewis et
al., 1993). Cortisol, which is released as part of the fight-or-flight response, is often used as a marker of
stress. Four-month-old Japanese infants showed a pronounced cortisol response, suggesting that they
were experiencing great stress, coupled with little crying. The U.S. infants, on the other hand, displayed
intense behavioral reactions to the pain and took longer to calm down, yet they displayed a lower
cortisol response. In other words, although the Japanese babies appeared quiet and calm, they were
more physiologically stressed than the U.S. infants. It seems that cultural views of the nature of arousal
and emotional regulation influence parenting behaviors and ultimately infants’ responses to stressors
(Friedlmeier et al., 2015).
Culture plays a role in emotional development. Japanese mothers tend to
encourage their infants to develop close ties and depend on their assistance
whereas North American mothers tend to emphasize autonomy.
Dukas/Universal Images Group via Getty Images
What constitutes an adaptive match between infant temperament and context—goodness of fit—is
sometimes surprising. Consider the Maasai, an African semi-nomadic ethnic group. In times of drought,
when the environment becomes extremely hostile, herds of cattle and goats die, and infant mortality
rises substantially. Under these challenging conditions, infants with difficult temperaments tend to
survive at higher rates than do those with easy temperaments. Infants who cry and are demanding are
attended to, are fed more, and are in better physical condition than easy babies, who tend to cry less
and therefore are assumed to be content (Gardiner & Kosmitzki, 2018). Thus, the Maasai infants with
difficult temperaments demonstrate higher rates of survival because their temperaments better fit the
demands of the hostile context in which they are raised. Temperament, therefore, must be considered in
context.
Thinking in Context: Lifespan Development
1. Under what conditions might temperament change, if at all? Is it possible for an infant with a
difficult temperament to grow into a young child with an easy temperament? Why or why not?
What experiences might cause temperament to mellow, or become more easygoing?
2. Can an easy child shift to show a difficult temperament? Explain.
3. In what ways do temperaments—and preferences for particular forms of temperament—vary
across cultures? How might these differences reflect adaptations to specific contextual conditions?
4. To what extent do temperaments and preferences for particular temperaments occur across the
many contexts within the United States? Are some infant temperaments a better fit for some
contexts than others? Why or why not?
ATTACHMENT IN INFANCY AND TODDLERHOOD
LEARNING OBJECTIVE
6.4 Examine the development of attachment and influences on attachment stability and outcomes
in infancy and toddlerhood.
Raj gurgles and cries out while lying in his crib. As his mother enters the room, he squeals excitedly. Raj’s
mother smiles as she reaches into the crib, and Raj giggles with delight as she picks him up. Raj and his
mother have formed an important emotional bond, called attachment. Attachment refers to a lasting
emotional tie between two people who each strive to maintain closeness to the other and act to ensure
that the relationship continues.
Attachment relationships serve as an important backdrop for emotional and social development. Our
earliest attachments are with our primary caregivers, most often our mothers. It was once thought that
feeding determined patterns of attachment. Freud, for example, emphasized the role of feeding and
successful weaning on infants’ personality and well-being. Behaviorist theorists explain attachment as
the result of infants associating their mothers with food, a powerful reinforcer that satisfies a biological
need. Certainly, feeding is important for infants’ health and well-being and offers opportunities for the
close contact needed to develop attachment bonds, but feeding itself does not determine attachment.
In one famous study, baby rhesus monkeys were reared with two inanimate surrogate “mothers”: one
made of wire mesh and a second covered with terrycloth (Figure 6.1). The baby monkeys clung to the
terrycloth mother despite being fed only by the wire mother, suggesting that attachment bonds are not
based on feeding but rather on contact comfort (Harlow & Zimmerman, 1959). So how does an
attachment form, and what is its purpose?
Description
Figure 6.1 Harlow’s Study: Contact Comfort and the Attachment Bond
Source: Harlow (1958); Photo Researchers, Inc./Science Source
Bowlby’s Ethological Theory of Attachment
John Bowlby, a British psychiatrist, posed that early family experiences influence emotional disturbances
not through feeding practices, conditioning, or psychoanalytic drives but via inborn tendencies to form
close relationships. Specifically, Bowlby (1969, 1988) developed an ethological theory of attachment that
characterizes it as an adaptive behavior that evolved because it contributed to the survival of the human
species. Inspired by ethology, particularly by Lorenz’s work on the imprinting of geese (Chapter 1) and
by observations of interactions of monkeys, Bowlby posited that humans are biologically driven to form
attachment bonds with other humans. An attachment bond between caregivers and infants ensures that
the two will remain in close proximity, thereby aiding the survival of the infant and, ultimately, the
species. From this perspective, caregiving responses are inherited and are triggered by the presence of
infants and young children.
Infants’ Signals and Adults’ Responses
From birth, babies develop a repertoire of behavior signals to which adults naturally attend and respond,
such as smiling, cooing, and clinging. Crying is a particularly effective signal because it conveys negative
emotion that adults can judge reliably, and it motivates adults to relieve the infants’ distress. Adults are
innately drawn to infants, find infants’ signals irresistible, and respond in kind. One recent study found
that nearly 700 mothers in 11 countries (Argentina, Belgium, Brazil, Cameroon, France, Kenya, Israel, Italy,
Japan, South Korea, and the United States) tended to respond to their infants’ cries and distress by
picking up, holding, and talking to their infants (Bornstein et al., 2017). Infants’ behaviors, immature
appearance, and even smell draw adults’ responses (Kringelbach et al., 2016). Infants, in turn, are
attracted to caregivers who respond consistently and appropriately to their signals. During the first
months of life, infants rely on caregivers to regulate their states and emotions—to soothe them when
they are distressed and help them establish and maintain an alert state (Thompson, 2013). Attachment
behaviors provide comfort and security to infants because they bring babies close to adults who can
protect them.
Magnetic resonance imaging (MRI) scans support a biological component to attachment because firsttime mothers show specific patterns of brain activity in response to infants. Mothers’ brains light up with
activity when they see their own infants’ faces, and areas of the brain that are associated with rewards
are activated in response to happy, but not sad, infant faces (Strathearn et al., 2008). In response to their
infants’ cries, U.S., Chinese, and Italian mothers show brain activity in regions associated with auditory
processing, emotion, and the intention to move and speak, suggesting automatic responses to infant
expressions of distress (Bornstein et al., 2017).
Phases of Attachment
Bowlby proposed that attachment formation progresses through several developmental phases during
infancy, from innate behaviors that bring the caregiver into contact to a mutual attachment relationship.
With each phase, infants’ behavior becomes increasingly organized, adaptable, and intentional.
Phase 1: Pre-Attachment—Indiscriminate Social Responsiveness (birth to 2
months).
Infants instinctively elicit caregiving responses from caregivers by crying, smiling, and making eye
contact with adults. Infants respond to any caregiver who reacts to their signals, whether parent,
grandparent, child care provider, or sibling.
Phase 2: Early Attachments—Discriminating Sociability (2 to 6–7 months).
When caregivers are sensitive and consistent in responding to babies’ signals, babies learn to associate
their caregivers with the relief of distress, forming the basis for an initial bond. Babies begin to
discriminate among adults and prefer familiar people. They direct their responses toward a particular
adult or adults who are best able to soothe them.
Phase 3: Attachments (7 to 24 months).
Infants develop attachments to specific caregivers who attend, accurately interpret, and consistently
respond to their signals. Infants can gain proximity to caregivers through their own motor efforts, such
as crawling.
Phase 4: Reciprocal Relationships (24 to 30 months and onward).
With advances in cognitive and language development, children can engage in interactions with their
primary caregiver as partners, taking turns and initiating interactions within the attachment relationship.
They begin to understand others’ emotions and goals and apply this understanding through strategies
such as social referencing.
Secure Base, Separation Anxiety, and Internal Working Models
The formation of an attachment bond is crucial for infants’ development because it enables infants to
begin to explore the world, using their attachment figure as a secure base, or foundation, to return to
when frightened. When infants are securely attached to their caregivers, they feel confident to explore
the world and to learn by doing so. As clear attachments form, starting at about 7 months, infants are
likely to experience separation anxiety (sometimes called
), a reaction to separations
from an attachment figure that is characterized by distress and crying (Lamb & Lewis, 2015). Infants may
follow, cling to, and climb on their caregivers in an attempt to keep them near.
separation protest
Separation anxiety tends to increase between 8 and 15 months of age, and then it declines. This pattern
appears across many cultures and environments as varied as those of the United States, Israeli
kibbutzim, and !Kung hunter-gatherer groups in Africa (Kagan et al., 1994). It is the formation of the
attachment bond that makes separation anxiety possible, because infants must feel connected to their
caregivers in order to feel distress in the caregivers’ absence. Separation anxiety declines as infants
develop reciprocal relationships with caregivers, increasingly use them as secure bases, and can
understand and predict parents’ patterns of separation and return, reducing their confusion and distress.
The attachment bond developed during infancy and toddlerhood influences personality development
because it comes to be represented as an internal working model, which includes the children’s
expectations about whether they are worthy of love, of whether their attachment figures will be available
during times of distress, and how they will be treated. The internal working model influences the
development of self-concept, or sense of self, in infancy and becomes a guide to later relationships
throughout life (Bretherton & Munholland, 2016).
Ainsworth’s Strange Situation
Virtually all infants form an attachment to their parents, but Canadian psychologist Mary Salter
Ainsworth proposed that infants differ in security of attachment—the extent to which they feel that
parents can reliably meet their needs. Like Bowlby, Ainsworth believed that infants must develop a
dependence on parents, viewing them as a metaphorical secure base, in order to feel comfortable
exploring the world (Salter, 1940). To examine attachment, Mary Ainsworth developed the Strange
Situation, a structured observational procedure that reveals the security of attachment when the infant
is placed under stress. As shown in Table 6.2, the Strange Situation is a heavily structured observation
task consisting of eight 3-minute-long episodes. In each segment, the infant is with the parent (typically
the mother), with a stranger, with both parent and stranger, or alone. Researchers observe infants’
exploration of the room, their reaction when the mother leaves the room, and, especially, their responses
during reunions, when the mother returns.
Table 6.2 The Strange Situation
Event
Experimenter introduces mother and infant to
playroom and leaves.
Infant plays with toys and parent is seated.
Stranger enters, talks with caregiver, and approaches
infant.
Mother leaves room; stranger responds to baby if
upset.
Mother returns and greets infant.
Mother leaves room.
Stranger enters room and offers comfort to infant.
Mother returns and greets infant. Tries to interest the
infant in toys.
Attachment Behavior Observed
Mother as secure base
Reaction to unfamiliar adult
Reaction to separation from mother
Reaction to reunion
Reaction to separation from mother
Reaction to stranger and ability to be soothed
by stranger
Reaction to reunion
On the basis of responses to the Strange Situation, infants are classified into one of several attachment
types (Ainsworth et al., 1978).
Secure Attachment: The securely attached infant uses the parent as a secure base, exploring the
environment and playing with toys in the presence of the parent, but regularly checking in (e.g., by
looking at the parent or bringing toys). The infant shows mild distress when the parent leaves. On
the parent’s return, the infant greets the parent enthusiastically, seeks comfort, and then returns to
individual play. About two-thirds of North American infants who complete the Strange Situation are
classified as securely attached (Lamb & Lewis, 2015).
Insecure–Avoidant Attachment: Infants who display an insecure–avoidant attachment show little
interest in the mother and busily explore the room during the Strange Situation. The infant is not
distressed when the mother leaves and may react to the stranger in similar ways as to the mother.
The infant ignores or avoids the mother on return or shows subtle signs of avoidance, such as
failing to greet her or turning away from her. About 15% of samples of North American infants’
responses to the Strange Situation reflect this style of attachment (Lamb & Lewis, 2015).
Insecure–Resistant Attachment: Infants with an insecure–resistant attachment show a mixed pattern
of responses to the mother. The infant remains preoccupied with the mother throughout the
procedure, seeking proximity and contact, clinging even before the separation. When the mother
leaves, the infant is distressed and cannot be comforted. During reunions, the infant’s behavior
suggests resistance, anger, and distress. The infant might seek proximity to the mother and cling to
her while simultaneously pushing her away, hitting, or kicking. About 10% of North American infants
tested in the Strange Situation fall into this category (Lamb & Lewis, 2015).
Insecure–Disorganized Attachment: A fourth category was added later to account for the small set
of infants (10% or below) who show inconsistent, contradictory behavior in the Strange Situation.
The infant with insecure-disorganized attachment shows a conflict between approaching and
fleeing the caregiver, suggesting fear (Main & Solomon, 1986). Infants showing insecuredisorganized attachment experience the greatest insecurity, appearing disoriented and confused.
They may cry unexpectedly and may show a flat, depressed emotion and extreme avoidance or
fearfulness of the caregiver.
Mary Ainsworth (1913–1999) believed that infants differ in the security of
attachment. She created the Strange Situation to measure infants’ security of
attachment.
JHU Sheridan Libraries/Gado/Getty Images
Attachment-Related Outcomes
Secure parent–child attachments are associated with positive socioemotional development in infancy,
childhood, and adolescence. Preschool and school-age children who were securely attached as infants
tend to be more curious, empathetic, self-confident, and socially competent, and they will have more
positive interactions and close friendships with peers (Groh et al., 2017; Veríssimo et al., 2014). The
advantages of secure attachment continue into adolescence. Adolescents who were securely attached in
infancy and early childhood are more socially competent, tend to be better at making and keeping
friends and functioning in a social group, and demonstrate greater emotional health, self-esteem, ego
resiliency, and peer competence (Boldt et al., 2014; Sroufe, 2016; Stern & Cassidy, 2018).
In contrast, insecure attachment is associated with heightened physiological reactivity and maladaptive
responses to interpersonal stressors, including elevated cortisol levels, a response to stress (Groh &
Narayan, 2019). Insecure attachment in infancy, particularly disorganized attachment, is associated with
long-term negative outcomes, including less positive and more negative affect, poor emotional
regulation, poor peer relationships, poor social competence, and higher rates of antisocial behavior,
depression, and anxiety from childhood into adulthood (Cooke et al., 2019; Groh et al., 2017; Wolke et
al., 2014; Zajac et al., 2020) Insecure attachments tend to correlate with difficult life circumstances and
contexts, such as parental problems, low socioeconomic status (SES), and environmental stress, that
persist throughout childhood and beyond, that influence the continuity of poor outcomes (Granqvist et
al., 2017). One longitudinal study suggested that infants with an insecure-disorganized attachment at 12
and 18 months of age were, as adults, more likely to have children with insecure-disorganized
attachment, suggesting the possibility of intergenerational transmission of insecure attachment (and
associated negative outcomes) (Raby et al., 2015).
Conversely, attachment is not set in stone. Quality parent–child interactions can at least partially make
up for poor interactions early in life. Children with insecure attachments in infancy who experience
subsequent sensitive parenting show more positive social and behavioral outcomes in childhood and
adolescence than do those who receive continuous care of poor quality (Sroufe, 2016). In addition,
infants can form attachments to multiple caregivers with secure attachments, perhaps buffering the
negative effects of insecure attachments (Boldt et al., 2014).
Influences on Attachment
The most important determinant of infant attachment is the caregiver’s ability to consistently and
sensitively respond to the child’s signals (Ainsworth et al., 1978; Behrens et al., 2011). Infants become
securely attached to mothers who are sensitive and offer high-quality responses to their signals, who
accept their role as caregiver, who are accessible and cooperative with infants, who are not distracted by
their own thoughts and needs, and who feel a sense of efficacy (Gartstein & Iverson, 2014). Mothers of
securely attached infants provide stimulation and warmth and consistently synchronize or match their
interactions with their infants’ needs (Beebe et al., 2010). Secure mother–infant dyads show more
positive interactions and fewer negative interactions compared with insecure dyads (Guo et al., 2015).
The goodness of fit between the infant's and parent’s temperament influences attachment, supporting
the role of reciprocal interactions in attachment (Seifer et al., 2014).
Infants who are insecurely attached have mothers who tend to be more rigid, unresponsive, inconsistent,
and demanding (Gartstein & Iverson, 2014). The insecure-avoidant attachment pattern is associated with
parental unavailability or rejection. Insecure-resistant attachment is associated with inconsistent and
unresponsive parenting. Parents may respond inconsistently, offering overstimulating and intrusive
caregiving at times and unresponsive care that is not attentive to the infant’s signals at other times.
Frightening parental behavior (at the extreme, child abuse) is thought to play a role in insecuredisorganized attachment (Duschinsky, 2015). Disorganized attachment is more common among infants
who have been abused or raised in particularly poor caregiving environments, but disorganized
attachment itself is not an indicator of abuse (Granqvist et al., 2017; Lamb & Lewis, 2015).
The most important determinant of infant attachment is the caregiver’s
ability to respond to the child’s signals consistently and sensitively.
iStock/aywan88
Attachment is complex and influenced by the contextual factors outside of the parent–infant
relationship. Conflict among parents is associated with lower levels of attachment security (Tan et al.,
2018). Insecure attachment responses may represent adaptive responses to poor caregiving
environments (Weinfield et al., 2008). Not relying on an unsupportive parent (such as by developing an
insecure-avoidant attachment) may represent a good strategy for infants. Toddlers who show an
avoidant attachment tend to rely on self-regulated coping rather than turning to others, perhaps an
adaptive response to an emotionally absent parent (Zimmer-Gembeck et al., 2017). Mental health
problems can influence parents’ emotional availability.
Maternal Depression and Attachment
Caregiver depression poses risks for attachment. Depression is not simply sadness; rather, it is
characterized by a lack of emotion and a preoccupation with the self that makes it difficult for depressed
mothers to recognize their infants’ needs and provide care. Both mothers and fathers can become
depressed, but most of the research examines mothers. The hormonal and social changes that
accompany pregnancy and new motherhood place women at risk for postpartum depression,
depression that occurs in the months after childbirth. However, depression can occur at any time in life.
Mothers who are depressed tend to view their infants differently than nondepressed mothers and
independent observers (Newland et al., 2016). They are more likely to identify negative emotions (i.e.,
sadness) than positive emotions (i.e., happiness) in infant faces (Webb & Ayers, 2015). Challenging
behaviors, such as fussiness and crying, and difficult temperaments tend to elicit more negative
responses from depressed mothers (Newland et al., 2016). When depressed and nondepressed mothers
were shown images of their own and unfamiliar infants’ joy and distressed faces, mothers with
depression showed blunted brain activity in response to their own infants’ joy and distressed faces,
suggesting muted responses to infants’ emotional cues (Laurent & Ablow, 2013). Depressed women
tend to disengage faster from positive and negative infant emotional expressions (Webb & Ayers, 2015).
In practice, mothers who are depressed tend to be less responsive to their babies, show less affection,
use more negative forms of touch, and show more negative emotions and behaviors such as withdrawal,
intrusiveness, hostility, coerciveness, and insensitivity (Jennings et al., 2008). Given the poor parent–child
interaction styles that accompany maternal depression, it may not be surprising that infants of
depressed mothers show a variety of negative outcomes, including insecure attachment, overall distress,
withdrawn behavior, poor social engagement, and difficulty regulating emotions (Barnes & Theule, 2019;
Granat et al., 2017; Leventon & Bauer, 2013). They tend to show greater physiological arousal in
response to stressors, difficulty reading and understanding others’ emotions, and are at risk for later
problems in development (Liu et al., 2017; Prenoveau et al., 2017; Suurland et al., 2017).
The ongoing reciprocal interactions between mothers and infants account for the long-term negative
effects of maternal depression (Granat et al., 2017). In one study, maternal depressive symptoms 9
months after giving birth predicted infants’ negative reactions to maternal behavior at 18 months of age
and, in turn, higher levels of depressive symptoms on the part of mothers when the children reached 27
months of age (Roben et al., 2015).
Depression is characterized by a lack of emotion and a preoccupation with
the self that makes it challenging for depressed mothers to care for their
infants and recognize their infants’ needs.
iStock/monkeybusinessimages
Yet low sensitivity is not always associated with poor outcomes. infants sometimes develop secure
attachments to caregivers who are less sensitive as long as their basic needs are met and they maintain a
calm regulated state (Cassidy et al., 2005). One study of 4.5-month-old infants from predominantly
Black, white, and Hispanic low socioeconomic status homes, found that caregiver provision of a secure
base (meeting basic needs and fostering a sense of calm) predicted attachment even in the presence of
caregiver insensitivity (Woodhouse et al., 2020). Infants’ brains may be predisposed to form attachments,
regardless of the quality of care (Opendak & Sullivan, 2019). In addition, infants develop attachments to
other members of the family system, such as fathers (Cabrera et al., 2014; Lickenbrock & BraungartRieker, 2015). (Dagan & Sagi-Schwartz, 2018).
Father–Infant Attachment
At birth, fathers interact with their newborns much like mothers do. They provide similar levels of care by
cradling the newborn and performing tasks like diaper changing, bathing, and feeding the newborn
(Combs-Orme & Renkert, 2009). This is true of fathers in Western contexts as well as those in nonWestern contexts, such as the Kadazan of Malaysia and Aka and Bofi of Central Africa (Hewlett &
MacFarlan, 2010; Hossain et al., 2007; Tamis-LeMonda et al., 2009).
Early in an infant’s life fathers and mothers develop different play and communicative styles. Fathers
tend to be more stimulating and physical while mothers are more soothing (Feldman, 2003; Grossmann
et al., 2002). Fathers tend to engage in more unpredictable rough-and-tumble play that is often met with
more positive reactions and arousal from infants; when young children have a choice of an adult play
partner, they tend to choose their fathers (Feldman, 2003; Lamb & Lewis, 2016).
Differences in mothers’ and fathers’ interaction styles appear in many cultures, including France,
Switzerland, Italy, and India, as well as among white non-Hispanic, African American, and Hispanic
American families in the United States (Best et al., 1994; Hossain et al. 1997; Roopnarine et al., 1992).
Interaction styles differ more in some cultures than in others. For example, German, Swedish, and Israeli
kibbutzim fathers, as well as fathers in the Aka ethnic group of Africa’s western Congo basin, are not
more playful than mothers (Frodi et al., 1983; Hewlett, 2008; Hewlett et al., 1998; Sagi et al., 1985).
Furthermore, overall and across cultures, most of the differences between mothers and fathers are not
large (Lamb & Lewis, 2016).
Fathers tend to have different interaction styles than mothers. Father–infant
interaction tends to be play-oriented. This is true of fathers in Western
contexts as well as those in non-Western contexts, such as the Kadazan of
Malaysia and Aka and Bofi of Central Africa.
iStock/kate_sept2004
Father–child interaction is associated with social competence, independence, and cognitive development
in children (Cabrera et al., 2018; Sethna et al., 2016). Fathers provide opportunities for babies to practice
arousal management by providing high-intensity stimulation and excitement, like tickling, chasing, and
laughing (Flanders et al., 2009). Fathers who are sensitive, supportive, and appropriately challenging
during play promote father–infant attachment relationships (Lickenbrock & Braungart-Rieker, 2015;
Olsavsky et al., 2020). When fathers are involved in the caregiving of their infants, their children are more
likely to enjoy a warm relationship with their father as they grow older, carry out responsibilities, follow
parents’ directions, and be well adjusted. Similar to findings with mothers, sensitive parenting on the
part of fathers predicts secure attachments with their children through age 3 (Brown et al., 2012;
Lucassen et al., 2011; Olsavsky et al., 2020). The positive social, emotional, and cognitive effects of
father–child interaction continues from infancy into childhood and adolescence (Cabrera et al., 2018;
Sarkadi et al., 2008). In addition, an infant’s secure attachment relationship with a father can compensate
for the negative effects of an insecure attachment to a mother (Boldt et al., 2014; Dagan & SagiSchwartz, 2018; Kochanska & Kim, 2013).
Stability of Attachment
Attachment patterns tend to be stable over infancy and early childhood, especially when securely
attached infants receive continuous responsive care (Ding et al., 2014; Marvin et al., 2016). The loss of a
parent, parental divorce, a parent’s psychiatric disorder, and physical abuse, as well as changes in family
stressors, adaptive processes, and living conditions, can transform a secure attachment into an insecure
attachment pattern later in childhood or adolescence (Feeney & Monin, 2016; Lyons-Ruth & Jacobvitz,
2016).
Contextual factors such as low SES, family and community stressors, and the availability of supports
influence the stability of attachment through their effect on parents’ emotional and physical resources
and the quality of parent–infant interactions (Booth-LaForce et al., 2014; Thompson, 2016; Van Ryzin et
al., 2011). Securely attached infants reared in contexts that pose risks to development may develop
insecure attachments, and insecure attachments tend to continue in risky contexts (Pinquart et al., 2013).
An insecure attachment between child and parent can be overcome by changing maladaptive
interaction patterns, increasing sensitivity on the part of the parent, and fostering consistent and
developmentally appropriate responses to children’s behaviors.
Cultural Variations in Attachment Classifications
Attachment occurs in all cultures, but whether the Strange Situation is applicable across cultural contexts
is a matter of debate. Research has shown that infants in many countries, including Germany, Holland,
Japan, and the United States, approach the Strange Situation in similar ways (Sagi et al., 1991). In
addition, the patterns of attachment identified by Ainsworth occur in a wide variety of cultures in North
America, Europe, Asia, Africa, and the Middle East (Bornstein et al., 2013; Cassibba et al., 2013; Huang et
al., 2012; Jin et al., 2012; Thompson, 2013).
Description
Figure 6.2 Cross-Cultural Variations in Attachment
Source: Adapted from Van Ijzendoorn & Kroonenberg (1988).
Nevertheless, there are differences. Insecure-avoidant attachments are more common in Western
European countries, and insecure-resistant attachments are more prevalent in Japan and Israel (Van
Ijzendoorn & Kroonenberg, 1988) (Figure 6.2). This pattern may result from the fact that Western
cultures tend to emphasize individuality and independence, whereas Eastern cultures are more likely to
emphasize the importance of relationships and connections with others, collectivism. Individualist and
collectivist cultural perspectives interpret children’s development in different ways (Keller, 2018). Western
parents might interpret insecure-resistant behavior as clingy, whereas Asian parents might interpret it as
successful bonding (Gardiner & Kosmitzki, 2018).
The behaviors that characterize sensitive caregiving vary with culturally specific socialization goals,
values, and beliefs of the parents, family, and community (Keller, 2019; Mesman et al., 2016). For
example, Puerto Rican mothers often use more physical control in interactions with infants, such as
picking up crawling infants and placing them in desired locations, over the first year of life than do
European American mothers. They actively structure interactions in ways consistent with long-term
socialization goals oriented toward calm, attentive, and obedient children. Typically, attachment theory
conceptualizes this type of control as insensitive, yet physical control is associated with secure
attachment status at 12 months in Puerto Rican infants (but not white non-Hispanic infants) (Carlson &
Harwood, 2003; Harwood et al., 1999). Similarly, German mothers operate according to the shared
cultural belief that infants should become independent at an early age and should learn that they cannot
rely on the mother’s comfort at all times. German mothers may seem unresponsive to their children’s
crying, yet they are demonstrating sensitive childrearing within their context (Grossmann et al., 1985). In
other words, the behaviors that reflect sensitive caregiving vary with culture because they are
adaptations to different circumstances (Rothbaum et al., 2000).
Many Japanese and Israeli infants become highly distressed during the Strange Situation and show high
rates of insecure resistance. Resistance in Japanese samples of infants can be attributed to cultural
childrearing practices that foster mother–infant closeness and physical intimacy that leave infants
unprepared for the separation episodes; the Strange Situation may be so stressful for them that they
resist comforting (Takahashi, 1990). In other words, the Strange Situation may not accurately measure
the attachment of these infants. Similarly, infants who are raised in small, close-knit Israeli kibbutz
communities do not encounter strangers in their day-to-day lives, so the introduction of a stranger in
the Strange Situation procedure can be overly challenging for them. At the same time, kibbutz-reared
infants spend much of their time with their peers and caregivers and see their parents infrequently and
therefore may prefer to be comforted by people other than their parents (Sagi et al., 1985).
Dogon infants from Mali, West Africa, show rates of secure attachment that are similar to those of
Western infants, but the avoidant attachment style is not observed in samples of Dogon infants
(McMahan True et al., 2001). Dogon infant care practices diminish the likelihood of avoidant attachment
because the infant is in constant proximity to the mother. Infant distress is promptly answered with
feeding and infants feed on demand, so mothers cannot behave in ways that would foster avoidant
attachment.
Dogon infants from Mali, West Africa, show rates of secure attachment that
are similar to those of Western infants, but the avoidant attachment style is
not observed in samples of Dogon infants because infants are in constant
proximity to mothers who respond to infant distress promptly and feed
infants on demand.
Danita Delimont/Alamy Stock Photo
Although most research on attachment has focused on the mother–infant bond, we know that infants
form multiple attachments (Dagan & Sagi-Schwartz, 2018). Consider the Efe foragers of the Democratic
Republic of Congo, in which infants are cared for by many people, as adults’ availability varies with their
hunting and gathering duties (Morelli, 2015). Efe infants experience frequent changes in residence and
camp, exposure to many adults, and frequent interactions with multiple caregivers. It is estimated that
the Efe infant will typically come into contact with 9 to 14 and as many as 20 people within a 2-hour
period. Efe infants are reared in an intensely social community and develop many trusting relationships
—many attachments to many people (Morelli, 2015). The Western emphasis on mother–infant
attachment may fail to acknowledge the many other attachment bonds that Efe infants form. It is
important that all infants develop attachments with some caregivers, but which caregivers—whether
mothers, fathers, or other responsive adults—matters less than the bonds themselves.
Thinking in Context: Biological Influences
Examine attachment from an evolutionary developmental perspective. In an evolutionary sense, what
purpose might infant–caregiver attachment serve? Is there biological or adaptive value to forming an
attachment with a caregiver? Considering emotional development and the development of attachment,
what evidence can you identify to support a biological aspect to attachment?
Thinking in Context: Applied Developmental Science
Children reared in impoverished orphanages are at risk of receiving little attention from adults and
experiencing few meaningful interactions with caregivers.
1. What might these experiences mean for the development of attachment? What outcomes and
behaviors might you expect from children reared under such conditions?
2. Suppose that you are a developmental scientist. How might you help children reared under
conditions of deprivation? How can you help them develop secure attachments? Would you
develop an intervention? Work with infants case-by-case? What do you think?
3. There are many children in the United States who experience neglect, trauma, and poor interactions
with caregivers. Compare these cases with the extreme deprivation of children reared in
impoverished orphanages. What similarities and differences might you expect? Would you intervene
and treat these two groups of children in the same way?
Thinking in Context: Intersectionality
Many conclusions about infant–parent interactions and attachment are based on research conducted
with white non-Hispanic families.
1. To what extent do you think observations of infant–parent interactions in white non-Hispanic
families apply to families of color?
2. Consider interactions among race and ethnicity, socioeconomic status, religion, and cultural views
of parenting. What similarities and differences in infant–parent interactions might you expect?
3. How might parents’ experiences within the community, such as exposure to violence,
discrimination and racism, and poverty, as well as social support and connection, influence their
interactions with infants and young children?
THE SELF IN INFANCY AND TODDLERHOOD
LEARNING OBJECTIVE
6.5 Differentiate the roles of self-concept, self-recognition, and self-control in infant development.
What do babies know about themselves? When do they begin to know that they have a “self”—that they
are separate from the people and things that surround them? We have discussed the challenges that
researchers who study infants face. Infants cannot tell us what they perceive, think, or feel. Instead,
researchers must devise ways of inferring infants’ states, feelings, and thoughts. As you might imagine,
this makes it very challenging to study infants’ conceptions of self, as well as their awareness and
understanding of themselves.
Self-Awareness
Camille, 4 months of age, delights in seeing that she can make the mobile above her crib move by
kicking her feet. Her understanding that she can influence her world suggests that she has a sense of
herself as different from her environment (Rochat, 1998). Before infants can take responsibility for their
own actions, they must begin to see themselves as physically separate from the world around them.
Some developmental researchers believe that infants are born with a capacity to distinguish the self
from the surrounding environment (Meltzoff, 1990; Rochat, 2018). Newborns show distress at hearing a
recording of another infant’s cries but do not show distress at hearing their own cries, suggesting that
they can distinguish other infants’ cries from their own and thereby have a primitive notion of self
(Dondi et al., 1999). Newborns’ facial imitation, that is, their ability to view another person’s facial
expression and produce it (see Chapter 4), may also suggest a primitive awareness of self and others
(Meltzoff, 2007; Rochat, 2013, 2018). It is unclear whether these findings suggest that newborns have
self-awareness because infants cannot tell us what they know.
Others argue that an awareness of oneself is not innate but emerges by 3 months of age (Neisser, 1993).
Infants’ sense of body awareness emerges through interactions and body contact with their mothers
(Montirosso & McGlone, 2020). Some researchers believe that this emergence is indicated by infants’
awareness of the consequences of their own actions on others (Langfur, 2013). As infants interact with
people and objects, they learn that their behaviors have effects. With this awareness, they begin to
experiment to see how their behaviors influence the world around them, begin to differentiate
themselves from their environments, and develop a sense of self (Bigelow, 2017).
Self-Recognition
How do we know whether self-awareness is innate or develops in the early months of life? One way of
studying self-awareness in infants is to examine infants’ reactions to viewing themselves in a mirror. Selfrecognition, the ability to recognize or identify the self, is assessed by the “rouge test.” In this
experiment, a dab of rouge or lipstick is applied to an infant’s nose without the infant’s awareness—such
as under the pretext of wiping his or her face. The infant is then placed in front of a mirror (Bard et al.,
2006). Whether the infant recognizes himself or herself in the mirror depends on cognitive development,
especially the ability to engage in mental representation and hold images in one’s mind. Infants must be
able to retain a memory of their own image in order to display self-recognition in the mirror task. If the
infant has an internal representation of her face and recognizes the infant in the mirror as herself, she
will notice the dab of rouge and reach for her own nose.
Mirror recognition develops gradually and systematically (Brandl, 2018). From 3 months of age, infants
pay attention and react positively to their mirror image, and by 8 to 9 months of age they show
awareness of the tandem movement of the mirror image with themselves and play with the image,
treating it as if it is another baby (Bullock & Lutkenhaus, 1990). Some 15- to 17-month-old infants show
signs of self-recognition, but it is not until 18 to 24 months that most infants demonstrate selfrecognition by touching their nose when they notice the rouge mark in the mirror (Cicchetti et al., 1997).
Does experience with mirrors influence how infants respond to the rouge test? Interestingly, infants from
nomadic tribes with no experience with mirrors demonstrate self-recognition at the same ages as infants
reared in surroundings with mirrors (Priel & deSchonen, 1986). This suggests that extensive experience
with a mirror is not needed to demonstrate self-recognition in the mirror task. In addition, research with
Canadian toddlers shows that their performance on the mirror task is unrelated to their experience with
mirrors in the home (Courage et al., 2004).
Mirror recognition is not the only indicator of a sense of self—and may not be the earliest indicator. A
recent study suggests that self-recognition may develop before infants can succeed on the mirror task
(Stapel et al., 2017). Eighteen-month-old infants viewed photographs of their own face, the face of an
unfamiliar infant, the face of their caregiver, and the face of an unfamiliar caregiver, while their brain
activity was registered via electroencephalography (EEG). The infants showed more brain activity in
response to their own face, suggesting self-recognition, yet only one-half of these infants succeeded on
the mirror task. By 18 to 24 months of age, children begin to recognize themselves in pictures and refer
to themselves in the pictures as “me” or by their first names (Lewis & Brooks-Gunn, 1979). One study of
20- to 25-month-old toddlers showed that 63% could pick themselves out when they were presented
with pictures of themselves and two similar children (Bullock & Lutkenhaus, 1990). By 30 months of age,
nearly all of the children could pick out their own picture.
The mirror-recognition task recruits areas in the brain associated with self-reflection in adults. Toddlers
who exhibit mirror self-reflection show increased functional connectivity between frontal and
temporoparietal regions of the brain, relative to those toddlers who do not yet show mirror selfrecognition, suggesting that mirror self-recognition may be a good indicator of a sense of self in infancy
(Bulgarelli et al., 2019).
This toddler recognizes herself in the mirror, as shown by her touching the
rouge mark on her face.
Thierry Berrod, Mona Lisa Production/Science Source
With advances in self-awareness, toddlers begin to experience more complex emotions, including selfconscious emotions, such as embarrassment, shame, guilt, jealousy, and pride (Lewis & Carmody, 2008).
An understanding of self is needed before children can be aware of being the focus of attention and feel
embarrassment, identify with others’ concerns and feel shame, or desire what someone else has and feel
jealousy toward them. In a study of 15- to 24-month-old infants, only those who recognized themselves
in the mirror looked embarrassed when an adult gave them overwhelming praise. They smiled, looked
away, and covered their faces with their hands. The infants who did not recognize themselves in the
mirror did not show embarrassment (Lewis, 2011). A developing sense of self and the self-conscious
emotions that accompany it leads toddlers to have more complex social interactions with caregivers and
others—all of which contribute to the development of self-concept.
Emerging Self-Concept
In toddlerhood, between 18 and 30 months of age, children’s sense of self-awareness expands beyond
self-recognition to include a categorical self, a self-description based on broad categories such as sex,
age, and physical characteristics (Stipek et al., 1990). Toddlers describe themselves as “big,” “strong,”
“girl/boy,” and “baby/big kid.” Children use their categorical self as a guide to behavior. Once toddlers
label themselves by gender, they spend more time playing with toys stereotyped for their own gender.
Applying the categorical self as a guide to behavior illustrates toddlers’ advancing capacities for selfcontrol.
At about the same time as toddlers display the categorical self, they begin to show another indicator of
their growing self-understanding. As toddlers become proficient with language and their vocabulary
expands, they begin to use many personal pronouns and adjectives, such as “I,” “me,” and “mine,”
suggesting a sense of self in relation to others (Bates, 1990). Claims of possession emerge by about 21
months and illustrate children’s clear representation of “I” versus other (Levine, 1983), a milestone in selfdefinition and the beginnings of self-concept (Rochat, 2010).
Self-Control
Self-awareness and the emerging self-concept permit self-control, as one must be aware of oneself as
separate from others to comply with requests and modify behavior in accordance with caregivers’
demands. In order to engage in self-control, the infant must be able to attend to a caregiver’s
instructions, shift his or her attention from an attractive stimulus or task, and inhibit a behavior. Cortical
development, specifically the development of the frontal lobes, is responsible for this ability (Posner &
Rothbart, 2018). Between 12 and 18 months, infants begin to demonstrate self-control by their
awareness of, and compliance to, caregivers’ simple requests (Kaler & Kopp, 1990).
Although toddlers are known for asserting their autonomy, such as by saying no and not complying with
a caregiver’s directive, compliance is much more common (Kochanska, 2000). Paradoxically, when
parents encourage autonomous, exploratory behavior, their children are more likely to show compliance
to parental instructions in toddlerhood through early childhood (Laurin & Joussemet, 2017). Secure
attachment relationships and warm parenting are associated with effortful control, likely as securely
attached infants feel comfortable exploring their environment, which promotes autonomy (Frick et al.,
2018; Pallini et al., 2018). Toddlers’ capacities for self-control improve rapidly. Delay of gratification tasks
suggests that between 18 and 36 months toddlers become better able to control their impulses and wait
before eating a treat or playing with a toy (Białecka-Pikul et al., 2018; Cheng et al., 2018).
Infants make great strides in socioemotional development over the first two years of life, as summarized
in Table 6.3. Infants’ advances in emotional expression and regulation represent the interaction of
biological predispositions, such as inborn capacities for basic emotions and temperament, and
experience—particularly parent–child interactions—the contexts in which they are raised, and the
goodness of fit between infants’ needs and what their contexts provide. Infants’ gains in emotional and
social development and a growing sense of self form a socioemotional foundation for the physical and
cognitive changes that they will experience in the early childhood years.
Table 6.3 The Developing Self
Concept
Selfconcept
Description
Self-description and thoughts about the self
Emergence
Begins as a sense of
awareness in the early
months of life
SelfAwareness of the self as separate from the environment
Innate or develops in the
awareness
early months of life
SelfThe ability to recognize or identify the self; typically tested in 18–24 months
recognition mirror-recognition tasks
Categorical Self-description based on broad categories such as sex, age, 18–30 months
self
and physical characteristics; indicates the emergence of selfconcept
Source: Adapted from Butterworth (1992).
Thinking in Context: Lifespan Development
1. Provide examples of how infants’ developing sense of self reflects interactions among temperament,
emotional development, and attachment.
2. Compare families in Western cultures that emphasize individuality and Eastern cultures that value
collectivism. How might parents and other adults interact with babies and promote a sense of self?
How might babies in each of these cultures come to understand themselves? Might you expect
differences within a culture, such as intersectional differences among infants in the United States?
3. How might contextual factors, such as those that accompany being raised in an inner city, suburban
neighborhood, rural environment, or nomadic society, influence infants’ developing sense of self?
Would you expect the same pattern of development for self-recognition, self-concept, and selfcontrol across all contexts? Why or why not?
APPLY YOUR KNOWLEDGE
A friendly lab assistant escorts 12-month-old Cassie and her mother into a research playroom containing
special mirrors and hidden equipment to videotape their interactions. After providing instructions, the
lab assistant leaves the mother and Cassie alone, beginning a short procedure to study the security of
their attachment relationship. A female stranger enters the room to play with Cassie. Soon after, the
mother leaves and Cassie is alone with the stranger. The mother returns briefly, then leaves again; finally,
the stranger leaves the room and Cassie is left alone. During each short separation from her mother,
Cassie cries and wails. Surprised and disturbed to find Cassie so upset, her mother returns almost
immediately. She cannot soothe Cassie, who alternates between clinging to her mother and pushing her
away angrily, crying all the time.
“Is Cassie upset today?” asks the lab assistant.
“No, she’s always this way,” her mother smiled softly, “My Cassie is quite a handful. She’s what my
mother calls spirited. She’s unpredictable and strong willed. She’ll eat and nap when she’s ready—and
that changes all the time. My mother says I was the same way. I love my little girl, but sometimes I look
forward to her growing up.”
1. What was this procedure intended to study? How? Why?
2. What might Cassie’s behavior indicate about her security of attachment relationship to her mother
and her emotional development? Why?
3. What do we know about the stability of infant attachment? What is the likelihood that these
observations will influence Cassie’s attachment in childhood? Adulthood?
4. Comment on the goodness of fit between Cassie’s temperament and the parenting.
5. Laboratory methods such as this are intended to place participants, infants, under distress. The
parent’s behavior is the source of that distress, and the procedure also is distressful to parents. From
your perspective, what do researchers learn from such research? Should researchers use procedures
that elicit distress from children and parents? If you were a parent to an infant, would you be willing
to participate in such an experiment?
CHAPTER SUMMARY
6.1
Summarize the psychosocial tasks of infancy and toddlerhood.
The psychosocial task of infancy is to develop a sense of trust. If parents and caregivers are sensitive
to the infant’s physical and emotional needs and consistently fulfill them, the infant will develop a
basic sense of trust in his or her caregivers and the world. The task for toddlers is to learn to do
things for themselves and feel confident in their ability to maneuver themselves in their
environment. Psychosocial development is supported by warm and sensitive parenting and
developmentally appropriate expectations for exploration and behavioral control.
6.2
Describe emotional development and the role of contextual influences on emotional
development in infants and toddlers.
Newborns display some basic emotions, such as interest, distress, and disgust. Self-conscious
emotions, such as empathy, embarrassment, shame, and guilt, depend on cognitive development, as
well as an awareness of self, and do not emerge until about late infancy. With development, infants
use different and more effective strategies for regulating their emotions. At about 6 months old,
infants begin to use social referencing. Social referencing occurs in ambiguous situations, provides
children with guidance in how to interpret the event, and influences their emotional responses and
subsequent actions. Parents socialize infants to respond to and display their emotions in socially
acceptable ways. The emotions that are considered acceptable, as well as ways of expressing them,
differ by culture and context.
6.3
Discuss the styles and stability of temperament, including the role of goodness of fit in infant
development.
Temperament, the characteristic way in which an individual approaches and reacts to people and
situations, has a biological basis. Children are classified into three temperament styles: easy, slowto-warm-up, and difficult. Temperament is influenced by the interaction of genetic predispositions,
maturation, and experience. Temperament tends to be stable but there are developmental and
individual differences. An important influence on socioemotional development is the goodness of
fit between the child’s temperament and the environment around him or her, especially the parent’s
temperament and childrearing methods.
6.4
Examine the development of attachment and influences on attachment stability and outcomes in
infancy and toddlerhood.
From an ethological perspective, attachment is an adaptive behavior that evolved because it ensures
that the infant and caregiver will remain in close proximity, aiding the survival of the infant. Using
the Strange Situation, infants are categorized as securely attached or insecurely attached (insecure–
avoidant, insecure–resistant, or disorganized–disoriented). Secure attachments in infancy are
associated with social competence and socioemotional health. Attachment patterns are seen in a
wide variety of cultures around the world, but the behaviors that make up sensitive caregiving vary
depending on the socialization goals, values, and beliefs of the family and community, which may
vary by culture. Generally, infants become securely or insecurely attached to caregivers based on the
caregiver’s ability to respond sensitively to the child’s signals.
6.5
Differentiate the roles of self-concept, self-recognition, and self-control in infant development.
The earliest notion of self-concept, self-awareness, is evident in a primitive fashion at 3 months of
age. Self-recognition, as indicated by mirror self-recognition, develops gradually and systematically
in infants, but it is not until 18 to 24 months that a majority of infants demonstrate self-recognition
,
j
y
g
in the mirror test. Once children have a sense of self, they can experience more complex emotions,
such as self-conscious emotions. Self-awareness permits self-control as one must be aware of
oneself as an agent apart from others to comply with requests and modify behavior in accord with
caregivers’ demands.
Key Terms
Attachment
Autonomy versus shame and doubt
Basic emotions
Categorical self
Difficult temperament
Easy temperament
Emotional display rules
Emotion regulation
Goodness of fit
Insecure-Avoidant Attachment
Insecure-Disorganized Attachment
Insecure-Resistant Attachment
Internal working model
Secure Attachment
Secure base
Security of attachment
Self-conscious emotions
Self-recognition
Separation anxiety
Slow-to-warm-up temperament
Social referencing
Social smile
Strange Situation
Stranger wariness
Temperament
Trust versus mistrust
Lifespan Development at Work Part 2: Infancy and Toddlerhood
There are many opportunities to work with infants and their families. Some include daily contact, such as
through child care, and others entail more infrequent contact, such as in the health fields.
Child Care Director
Visitors to child care centers are most familiar with the child care worker or teacher who cares for infants
and toddlers. Who hires and supervises the child care workers? Who creates and administers programs?
Who oversees the operations of the center? Child care directors or administrators may not have daily
contact with each infant, but their work affects infants and parents each day.
Child care directors are responsible for the operating and leading the work of a child care center. They
play a lead role in constructing the center’s mission statement, the philosophy that guides the center’s
work. Child care directors lead teachers in creating instructional resources to use in class and develop
policies such as scheduling of outside time, naps, and other activities. They are also responsible for the
running the business, including advertising, maintaining financial records, and directing human
resources. Directors may market the center, take parents on tours of the facility, write budgets, and
prepare annual reports. Human resource activities include hiring, overseeing and evaluating employees,
and mediating disputes.
The requirements for becoming a child care director vary by state and center. Some require a bachelor’s
degree (or higher) in early childhood education. Others require a high school diploma. Some states and
centers may require experience as a child care staff member before becoming a director. Most require
directors of child care centers to have certification, such as the National Administration Credential (NAC),
which requires completion of a 45-hour course. The 2020 median salary for child care directors was
about $49,000 (U.S. Bureau of Labor Statistics, 2021).
Social Worker
Social workers work with individuals and families of all ages, providing counseling and identifying and
helping them access needed resources. Social workers are advisers who advocate for others during
transitions, crisis situations, and challenging circumstances. They help families navigate often confusing
federal and state programs to obtain needed assistance, such as access to the WIC program, a federal
program to promote the health of low-income
by providing nutritious
food, housing assistance, medical treatment, and other aid. Social workers may engage in education and
counseling, such as individual and group counseling sessions on topics such as parenting and coping
skills. A bachelor’s degree may offer preparation for entry-level positions in social work; a master’s
degree in social work (MSW) will provide many more opportunities, including independent practice as a
.
women, infants, and children
clinical social worker
Clinical social workers obtain master’s degrees, additional supervised experience, and pass a certification
exam to become licensed clinical social workers (LCSW). Clinical social workers provide psychological
treatment, including diagnosing and treating psychological, emotional, and behavioral disorders and
working with doctors and other medical professionals. They are employed in a variety of settings,
including hospitals, schools, community mental health centers, social service agencies, and private
practice. The median salary for clinical social workers was about $57,000 in 2019 (Graves, 2020).
Pediatric Nurse
There are many different kinds of nurses. Some specialize to work with specific populations, such as
infants and children. Becoming a nurse requires earning an associate degree or bachelor’s degree in
nursing, obtaining experience, and passing a licensing exam. The associate degree prepares nurses for
entry-level positions. Some employers prefer nurses with bachelor’s degrees in nursing. Bachelor’s
degrees provide more opportunities to advance. Becoming certified as a registered nurse (RN) opens
additional opportunities (and higher salaries). Certification as an RN requires two years of experience
and passing an exam. Opportunities and salaries increase with education and experience.
Pediatric nurses are registered nurses who specialize in caring for patients from infancy through
adolescence. Pediatric nurses perform physical examinations, measure vital statistics, educate parents
and caregivers, and work alongside other health care providers, such as physicians, to promote children’s
health and well-being. Because their patients are so young, pediatric nurses often develop close
connections with them and their families. An understanding of development is critical to the work of
pediatric nurses because infants, children, and adolescents have different abilities and needs—and these
change with development.
Pediatric nurses are found in hospitals, clinics, private practice, schools, and more. Becoming a pediatric
nurse entails completing nursing school, gaining experience, and completing a licensure exam. In
addition, pediatric nurses typically complete Certified Pediatric Nurse Examination to demonstrate their
competence. In 2020 the median pay for all registered nurses was about $75,000, but salaries vary with
education, experience, and geographic location (U.S. Bureau of Labor Statistics, 2021).
Pediatrician
Just as there are many types of nurses, there are many medical specialties and types of physicians (or
doctors). Becoming a physician requires attending medical school, which requires four years of
education beyond the bachelor’s degree. In addition to passing a licensure examination, physicians
complete a 3-year or longer residency program to gain hands-on experience and training within a
specialty. Some seek additional specialty certification by completing a board examination. Pediatricians
complete this process and specialize in treating infants, children, and adolescents.
Pediatricians provide treatment to infants, children, and adolescents to treat illnesses but also to
improve their overall health and well-being. They perform tasks like routine checkups, provide
immunizations and medications, order tests, refer patients to specialists for specific injuries or illnesses,
and speak with parents about their child’s treatment options. They assess children’s growth, determine
whether it is in the appropriate range, and if it is not, devise treatment plans. Pediatricians work in
hospital settings, clinics, and independent practice. Pediatricians earned a median salary of about
$185,000 in 2020 (U.S. Bureau of Labor Statistics, 2021).
Descriptions of Images and Figures
Back to Figure
The photo has an infant monkey feeding from the wire mother with the lower half of its body kept on
the cloth mother.
The two graphs are titled “FED ON CLOTH MOTHER” and “FED ON WIRE MOTHER” in which the
horizontal axes represent “DAYS OF AGE” and vertical axes represents “MEAN HOURS PER DAY.” The
horizontal axes have markings 1-5, 6-10, 11-15, 16-20, and 21-25, from left to right. The vertical axes
have markings from 0 to 24 in increments of 6.
The data from the graph “FED ON CLOTH MOTHER” are shown in the table below. Values are
approximate.
Cloth Mother
DAYS OF AGE
1-5
6-10
11-15
16-20
21-25
MEAN HOURS PER DAY
15
18
19
21
20
Wire Mother
MEAN HOURS PER DAY
1-5
1
6-10 1
11-15 1
16-20 1
21-25 1
The data from the graph “FED ON WIRE MOTHER” are shown in the table below. Values are approximate.
Cloth Mother
Wire Mother
DAYS OF AGE MEAN HOURS PER DAY
MEAN HOURS PER DAY
1-5
7
1-5
2
6-10
11-15
16-20
21-25
Back to Figure
9
11
16
17
6-10
11-15
16-20
21-25
1
2
3
3
The x-axis represents the percentage ranging from 0 to 80 and the y-axis represents the country. The
graph plots the data for Anxious/Avoidant, Anxious/Resistant and Secure. The data from the graph are
shown in the table below.
Country
Germany
Israel
United States
Netherlands
Japan
Anxious/Avoidant (%)
35.3
6.8
21.1
26.3
5.2
Anxious/Resistant (%)
8.6
28.8
14.1
6.4
27.1
Secure (%)
56.6
64.4
64.8
67.3
67.7
PART III EARLY CHILDHOOD
7 PHYSICAL AND COGNITIVE DEVELOPMENT IN EARLY
CHILDHOOD
Orbon Alija/Getty Images
George’s parents watched with pride as their 4-year-old son kicked the soccer ball to the other children.
George has grown from a bowlegged, round-tummied, and top-heavy toddler into a strong, wellcoordinated young child. His body slimmed, grew taller, and reshaped into proportions similar to that of
an adult. As a toddler, he often stumbled and fell, but George can now run, skip, and throw a ball. He has
also gained better control over his fingers; he can draw recognizable pictures of objects, animals, and
people. As his vocabulary and language skills have grown, George has become more adept at
communicating his ideas and needs.
How do these developments take place? In this chapter we examine the many changes that children
undergo in physical and motor development as well as how their thinking and language skills change.
GROWTH AND MOTOR DEVELOPMENT IN EARLY CHILDHOOD
LEARNING OBJECTIVE
7.1 Discuss physical growth, including motor and brain development, in early childhood.
George’s abilities to run, skip, and manipulate his fingers to create objects with Play-Doh illustrate the
many ways that children learn to control their bodies. In early childhood, children get taller, stronger, and
better able to control their bodies. Their developing motor skills permit them to engage in new activities
and interact with others in new ways.
Body Growth
As compared with the first 2 years of life, growth slows during early childhood. From ages 2 through 6,
the average child grows 2 to 3 inches taller and gains nearly 5 pounds in weight each year. The typical 6year-old child weighs about 45 pounds and is about 46 inches tall.
y
g
p
Body proportions change during early childhood as the body “catches up” with the head. The proportion
of body fat to muscle changes. Young children become more lean and both boys and girls gain muscle
can lose fat, but at 5 years of age girls have slightly more fat than boys and boys more muscle (Lloyd et
al., 2019). The cephalocaudal trend of infancy continues as the trunk, arms, and legs grow rapidly and
body proportions become similar to those of adults. Specifically, the long bones of the arms and legs
form new tissue through a process known as ossification. Ossification results in gains in height and armspan as the legs and arms grow; bones also become stronger and harder (Lloyd et al., 2019). As a result,
over early childhood young children’s bodies become less top-heavy, their bodies slim and legs become
longer, and they start to take on proportions that are similar to adults.
Children’s height and rate of growth are closely related to that of their parents (Kliegman et al., 2016).
Ethnic differences in growth patterns appear in developed nations such as England, France, Canada,
Australia, and the United States (Natale & Rajagopalan, 2014). Generally, children of African descent tend
to be tallest, followed by children of European descent, then Asian, then Latino. But there are many
individual differences. Even within a given culture, some families are much taller than others (Stulp &
Barrett, 2016). Contextual factors, such as access to nutrition and health care, also influence body
growth.
Motor Development
The refinement of motor skills that use the large muscles of the body—as well as those that require
hand–eye coordination and precise hand movements—is an important developmental task of early
childhood. In this section, we describe the typical sequence of development of gross and fine motor
skills.
Gross Motor Skills
Between the ages of 3 and 6, children become physically stronger, with increases in bone and muscle
strength. As the parts of the brain responsible for sensory and motor skills develop, children gain
balance and coordination and can run, stop suddenly, and turn, jump, hop, and climb. Young children are
driven to move and to practice motor skills. Three-year-old children show the highest level of activity in
the lifespan (Gabbard, 2018). As they grow and gain competence in their motor skills, young children
become more coordinated and begin to show interest in balancing games and those that involve feats
of coordination, such as running while kicking a ball. Coordinating complex movements, like those
entailed in riding a bicycle, is challenging for young children as it requires controlling multiple limbs,
balancing, and more. By age 5, most North American children can throw and catch a ball, climb a ladder,
and ride a tricycle. Some 5-year-olds can even skate or ride a bicycle (Gabbard, 2018). Table 7.1
summarizes gross motor milestones in young children.
Table 7.1 Gross Motor Skill Development in Early Childhood
Age Gross Motor Skill
2–3 Walks more smoothly, runs but cannot turn or stop suddenly, jumps, throws a ball with a rigid
years body and catches by trapping ball against chest, rides push toys using feet
Age
3–4
years
4–5
years
Gross Motor Skill
Runs, ascends stairs alternating feet, jumps 15 to 24 inches, hops, pedals and steers a tricycle
Runs more smoothly with control over stopping and turning, descends stairs alternating feet,
jumps 24 to 33 inches, skips, throws ball by rotating the body and transferring weight to one
foot, catches ball with hands, rides tricycle and steers effectively
5–6 Runs more quickly, skips more effectively, throws and catches a ball like older children, makes a
years running jump of 28 to 36 inches, rides bicycle with training wheels
There is continuity in motor development throughout childhood. Motor experience and achievements in
infancy are associated with motor skills in early childhood. Children who learn to crawl early tend to
show more advanced motor skills in early childhood than their late-crawling peers (Payne & Isaacs,
2020). Preschoolers who regularly engage in moderate to vigorous physical activity tend to show better
gross motor coordination (Silva-Santos et al., 2019).
Young children’s motor abilities unfold with maturation and are also influenced by their context.
Children in low socioeconomic status homes in the United States and the United Kingdom tend to
perform more poorly on measures of gross and fine motor development, perhaps because of nutritional
deficits, reduced opportunities for outside play, and other reductions in supports (Bellows et al., 2017;
Morley et al., 2015). A caregiver’s encouragement or discouragement of vigorous active play and
outdoor play influences children’s opportunities to practice and refine motor skills, and their gross
motor competence (Barnett et al., 2016).
Children learn new motor skills by experimenting with movement and discovering new abilities. They
also learn by observing other children and through play. Boys and girls show similar motor abilities, with
subtle differences. Boys tend to be more active than girls and can typically throw a ball and kick better
as well as jump farther than girls. Girls, on the other hand, tend to be better at coordinated activities
such as balancing on one foot. The games that boys and girls are typically encouraged to play
contribute to sex differences in motor skills. For example, boys often have more practice in games
involving balls and girls often play balancing games, such as hopscotch.
Climbing requires strength, coordination, and balance.
Michele Oenbrink/Alamy Stock Photo
The activities favored for children and those children therefore practice and master vary with cultural
context. Young children of some nations can swim in rough ocean waves that many adults of other
nations would not attempt. In one comparison, Brazilian children—raised in a culture that stresses
spontaneous, informal, playful, and physically active behavior—tended to outperform British children in
comparisons of vigorous activities such as running and jumping (Victora et al., 1990). The British
children, on the other hand, immersed in a culture that tended to encourage quiet, independent, and
self-contained activities that foster academic achievement excelled on fine motor movements as
compared with the Brazilian children. Advances in gross motor skills help children move about and
develop a sense of mastery of their environment, but it is fine motor skills that permit young children to
take responsibility for their own care.
Fine Motor Skills
Motor development follows the proximodistal principle (see Chapter 5). Children gain motor control
from the body outward toward the fingers and toes. Fine motor skills rely on controlling and
coordinating the small muscles of the body. The ability to button a shirt, pour milk into a glass, assemble
puzzles, and draw pictures all involve hand–eye and small muscle coordination. As children get better at
these skills, they can become more independent and do more for themselves. Young children become
better at grasping eating utensils and become more self-sufficient at feeding. Many fine motor skills are
difficult for young children because they involve both hands and both sides of the brain. Tying a
shoelace is a complex act requiring attention, memory for an intricate series of hand movements, and
the dexterity to perform them. Although preschoolers struggle with this task, by 5 to 6 years of age,
most children can tie their shoes (Payne et al., 2020). Dexterity is associated with reasoning, and
children’s ability to use their fingers to aid in counting predicts their mathematical skills (Fischer et al.,
2018, 2020; Martzog et al., 2019).
Young children's skills in drawing and writing illustrate the interaction of cognitive and motor domains
of development. Drawing reflects fine motor control, planning skills, spatial understanding, and the
recognition that pictures can symbolize objects, people, and events (Yamagata, 2007). Young children’s
emerging fine motor skills enable them to draw using large crayons and, eventually, pencils. Drawing
skills progress through a predictable sequence alongside cognitive, motor, and brain maturation
(Kellogg, 1970).
When given a crayon, toddlers scribble (Dunst & Gorman, 2009; Toomela, 2003). By 3 years of age,
children‘s scribbles become more controlled, often recognizable, pictures (Dunst & Gorman, 2009;
Toomela, 2003). Most 3-year-olds can draw circles, squares, rectangles, triangles, crosses, and Xs, and
they begin to combine shapes into more complex designs. If asked to draw a human figure, 3-year-olds
usually draw a tadpole-like figure with a circle for the head with eyes and sometimes a smiley mouth,
and then a line or two beneath to represent the rest of the body. Tadpole-like forms are characteristic of
young children’s art in all cultures (Cox, 1993). As shown in Figure 7.1, these tadpole-like human figures
typically are drawn with arms (and later legs) and legs attached directly to the head.
Figure 7.1 A Typical 3-Year-Old’s Drawing of a Person
Between 3 and 4 years of age, young children begin to understand the representational function of
drawings, and even when drawings appear to be nothing more than scribbles, young children often label
them as representing a particular object and remember the label. In one study, children were asked to
draw a balloon and a lollipop. The drawings looked the same to adults, but the children were adamant
about which was which (Bloom, 2000), suggesting that it is important to ask a child what their drawing is
rather than guess, because children’s creations reflect their perspectives. Between ages 4 and 5,
children’s drawings loosely begin to depict actual objects, demonstrating the convergence of fine motor
skills and the cognitive development of representational ability.
By age 4, children’s drawings of people continue to consist of simple figures, often with a circle
representing a torso or stomach (Cox, 1997). As cognitive and fine motor skills improve, children create
more sophisticated drawings of the human form in which the body parts are differentiated. Five-yearolds include a torso, and after 5, non-stick-like arms and hands are included (Cox, 1997). Even older
preschoolers’ drawings contain perceptual distortions. During middle childhood the use of depth
improves and children’s drawings become more perceptually realistic (Cox & Littlejohn, 1995). Overall,
fine motor skills, such as the ability to copy a design and write letters, predicts cognitive, reading,
academic achievement in preschool, kindergarten, and second grade (Cameron et al., 2012; Dinehart &
Manfra, 2013; Suggate et al., 2019). Table 7.2 summarizes milestones of fine motor skill development in
young children.
Table 7.2 Fine Motor Skill Development in Early Childhood
Age
2–3
years
3–4
years
4–5
years
5–6
years
Fine Motor Skill
Unzips large zippers, puts on and removes some clothing, uses a spoon
Serves food, can work large buttons, copies vertical line and circle, uses scissors
Uses scissors to cut along a line, uses fork effectively, copies simple shapes and some letters
Ties shoes, uses knife to cut soft food, copies numbers and simple words
Brain Development
Early childhood is a period of rapid brain growth, but synaptogenesis occurs at a slower pace than
infancy. The increase in synapses and connections among brain regions helps the brain to reach 90% of
its adult weight by age 5 (Dubois et al., 2013). In early childhood, the greatest increases in cortical
surface area are in the frontal and temporal cortex, which play a role in thinking, memory, language, and
planning (Gilmore et al., 2018).
Children’s brains tend to grow in spurts, with very rapid periods of growth followed by little growth or
even reductions in volume with synaptic pruning (see Chapter 4) (Jernigan & Stiles, 2017; Kolb, 2020).
Little-used synapses are pruned in response to experience, an important part of neurological
development that leads to more efficient thought. The natural forming and pruning of synapses enable
the human brain to demonstrate plasticity, the ability to change its organization and function in
response to experience (Di Cristo & Chattopadhyaya, 2020; Stiles, 2017). Young children who were given
training in music demonstrated structural brain changes over a period of 15 months that correspond
with increases in music and auditory skills (Hyde et al., 2009). Plasticity enables the young child’s brain to
reorganize itself in response to injury in ways that the adult’s brain cannot. Adults who suffered brain
injuries as older infants or young children often have fewer cognitive difficulties than do adults who
were injured later in life.
Yet the immature young brain, while offering opportunities for plasticity, is also uniquely sensitive to
injury. If a part of the brain is damaged at a critical point in development, functions linked to that region
can be irreversibly impaired. Generally speaking, plasticity is greatest when neurons are forming many
synapses, and it declines with pruning (Kolb et al., 2019). However, brain injuries sustained before age 2
and, in some cases, 3 can result in more global, severe, and long-lasting deficits than do those sustained
later in childhood (V. A. Anderson et al., 2014), suggesting that a reserve of neurons is needed for the
brain to show plasticity. Overall, the degree to which individuals recover from an injury depends on the
injury, its nature and severity, age, experiences after the injury, and contextual factors supporting
recovery, such as interventions (Bryck & Fisher, 2012).
Myelination contributes to many of the changes that we see in children’s capacities. As the neuron’s
axons become coated with fatty myelin, children’s thinking becomes faster, more coordinated, and
complex (Kolb, 2020). Myelination aids quick, complex communication between neurons and makes
coordinated behaviors possible (Chevalier et al., 2015). Patterns of myelination correspond with the
onset and refinement of cognitive functions and behaviors (Dean et al., 2014). Myelination proceeds
most rapidly from birth to age 4, first in the sensory and motor cortex, and then spreads to other cortical
areas through childhood, continuing through adolescence and into early adulthood (Qiu et al., 2015;
Reynolds et al., 2019).
Lateralization, the process of the hemispheres becoming specialized to carry out different functions,
becomes more pronounced in early childhood and is associated with children’s development (Kolb,
2020). Recall from Chapter 4 that infants generally display a hand preference, left or right, which tends to
strengthen with use. Hemispheric domination increases over childhood, and the left hemisphere tends
to dominate over the right in most adults (Duboc et al., 2015). Language tends to be lateralized to the
left hemisphere in adults, and lateralization predicts children’s language skills. Young children who show
better performance on language tasks use more pathways in the left hemisphere and fewer in the right
than those who are less skilled in language tasks (M. Walton et al., 2018).
Thinking in Context: Lifespan Development
Recall from Chapter 1 that domains of development interact. Consider this principle with regard to
physical development in early childhood.
1. How might changes in growth or motor skills influence other aspects of a child’s development, such
as cognitive or social development? Give examples.
2. Consider the reverse: Might other aspects of development, such as cognitive, emotional, or social
development, have implications for physical development? Why or why not?
3. How might the larger cultural context matter in influencing children’s brain development? Consider
the experiences of children from a Western country compared with children from a non-Western,
underdeveloped country. Do you expect cultural differences? Why or why not?
Thinking in Context: Biological Influences
1. Identify similarities and differences in patterns and processes of brain development in infancy
(Chapter 4) and early childhood.
2. A parent to a 3-year-old informs you, “I’d like to take advantage of the plasticity of the early
childhood brain.” Explain the concept of plasticity. Should the parent “take advantage” of it? How?
What do you tell the parent?
HEALTH AND THREATS TO HEALTH IN EARLY CHILDHOOD
LEARNING OBJECTIVE
7.2 Examine the influence of nutrition, physical activity, sleep, and screen use on young children’s
health as well as risks to health.
Early childhood is a healthy time in life. It is also a time in which children begin to develop interests and
patterns of health behaviors that can last a lifetime. Parents and caregivers can help young children
develop healthy eating, exercise, sleep, and screen use habits, as discussed next.
Nutrition and Eating Habits
Young children require a healthy diet, with the same foods that adults need. Most children in developed
nations eat enough calories, but their diets are often insufficient in vitamins and minerals, such as
vitamin D, calcium, and potassium, and often high in calories and sugar (Hess & Slavin, 2014). In one
study of 96 child care centers, 90% served high-sugar or high-salt food or did not serve whole grains in
a day’s meals (Benjamin Neelon et al., 2012). Nutrient-dense snacks, such as cheese, yogurt, or hummus,
can increase children’s intake of nutrients without contributing to dietary excess.
Children’s food preferences are influenced by their experiences. Repeated exposure to sweet and salty
snacks increases children’s preference for sugary and salty foods (Remington et al., 2012). Young
children are often sensitive to the sensory quality of foods, including appearance, texture, and shape
(Marotz, 2015). Parents model food preferences and children can acquire food preferences and dislikes
through observation (Hannon et al., 2003). Children often dislike trying new foods. Encouraging the child
to try the food several times over a few weeks can help the child become familiar with the taste and
texture, which can increase the likelihood of the child eating. Involving children in meal preparation can
improve children’s interest in and acceptance of new foods.
Young children require a healthy diet, which can be accompanied by an
occasional junk-food splurge.
Jose Luis Pelaez Inc./Getty Images
From ages 2 to 6, young children’s appetites vary with their growth. Children’s appetite is usually very
good during active growth periods, but their appetite declines as their growth slows (Marotz, 2015). This
decline is normal, but it is often an undue concern for parents. Children eat when they are hungry and
should be provided with frequent opportunities to eat. When a child doesn’t finish breakfast, a small
nutritious midmorning snack can make up for lost nutrients. Generally, preschool children tend to
balance their eating, making up for short periods of little food intake with greater consumption later
(Ball et al., 2017).
At around age 3, it is not uncommon for children to go through a fussy eating phase, where previously
tolerated food is no longer accepted and it is hard to introduce new food (Fildes et al., 2014). Estimates
of picky eating vary widely, but it is highest (14%–50%) in preschool children and tends to decline with
time (C. M. Taylor et al., 2015). Parents of picky eaters report that their children consume a limited variety
of foods, require foods to be prepared in specific ways, express strong likes and dislikes, and throw
tantrums over feeding. Children who are picky eaters are likely to consume fewer calories, fruits and
vegetables, and vitamins and minerals than other children. This behavior often raises parental concerns
about nutrition (P. K. Berger et al., 2016). Pediatricians tend to view picky eating as a passing phase, often
to the frustration of parents.
The overall incidence of picky eating declines with time, but for some children it is chronic, lasting for
several years. Children who are sensitive to touch are more aware of the tactile sensation of food in their
mouths, whether the food is crispy or slimy, thick or with bits, and are more likely to show picky eating
(Nederkoorn et al., 2015; Steinsbekk et al., 2017).
Persistent picky eating illustrates the dynamic interaction of developmental domains. Physical and
emotional factors, such as sensory sensitivity and temperament, can place children at risk for picky
eating, which in turn influences physical development (Hafstad et al., 2013; Steinsbekk et al., 2017).
Moreover, picky eating tends to elicit parental pressure to eat, which is associated with continued
pickiness, suggesting that picky eating is sustained through bidirectional parent–child interactions
(Jansen et al., 2017). Interventions for picky eating can help children learn to tolerate tactile sensations
and help parents to understand that parental responses to pickiness can influence children’s behavior
and sustain picky eating (K. Walton et al., 2017). For most children, picky eating is a phase with no
significant effect on growth (Jansen et al., 2017).
Many parents pressure children to eat, but picky eating is a common phase
with no effect on growth in most children.
iStock/Drazen Zigic
Children with developmental disabilities and health conditions may have different food needs and
experience feeding challenges (Samour & King, 2013). Impaired motor skills may make it difficult or
impossible for children to feed themselves. Medications may influence children’s appetite or their needs
for particular nutrients. Children may have difficulty recognizing the body signals for hunger or fullness.
Children with autistic spectrum disorders and sensory disorders may restrict their eating to particular
textures or colors and require coaxing to eat, especially new foods (Shmaya et al., 2017). Food allergies,
such as to dairy, wheat, or gluten, may make it difficult for children to gain the calories that they need.
Physical Activity
“Try to catch me!” 4-year-old Eduardo called out to his playmates in the yard and broke into a sprint.
Young children’s play often involves physical activity, with important benefits for development. An
analysis of nearly 100 studies conducted in 36 countries suggests that physical activity enhances growth
and is consistently associated with advances in motor development, fitness, and bone and skeletal
health (Carson et al., 2017). The recently updated Physical Activity Guidelines for Americans advises that
preschool children require daily physical activity and advises a target of about 3 hours of activity (at any
level ranging from light, such as walking at a comfortable place, to vigorous, running) per day (U.S.
Department of Health and Human Services, 2018). Over the course of a day a child might go for a walk
with a caregiver, engage in active play with peers, and practice dancing and balancing games in
preschool. Canada, the United Kingdom, and the Commonwealth of Australia have published similar
recommendations (U.S. Department of Health and Human Services, 2018).
Unfortunately, only about half of children meet the physical activity guidelines (Hesketh et al., 2017; Pate
et al., 2015). One important predictor of physical activity is time spent outdoors. Children are more active
when they are enrolled in care centers that schedule more than 1 hour of outside time each day
(Copeland et al., 2016). Access to safe play environments is also associated with greater physical activity.
Children who live in homes with yards engage in more physical activity than those who live in
apartments, and yard size is positively associated with children’s level of physical activity (J. M. Miller et
al., 2020). Children from low-income homes tend to spend less time outdoors, engage in less physically
active play, and spend more time in sedentary behaviors, such as watching television as reported by
parents (Lindsay et al., 2017). Although children of color are more likely to reside in communities that
may pose challenges to outside play, ethnic and racial differences are not apparent in preschoolers’
physical activity (Pate et al., 2015).
Sleep
Sleep duration naturally declines about 20% from infancy into early childhood (Honaker & Meltzer,
2014). The American Academy of Sleep Medicine advises that young children 3 to 5 years of age should
sleep 10 to 13 hours (including naps) each day (Paruthi et al., 2016). Most young children meet these
goals, sleeping 10 to 11 hours each night (Magee et al., 2014).
Some children experience sleep problems, such as awakening often, difficulty falling asleep, and poor
sleep duration. Poor sleep may have a cascading effect on development through its influence on brain
function. Sleep problems pose risks to young children’s cognitive development, including problems with
attention, working memory, and slower processing speed (Schumacher et al., 2017). Sleep deprivation
affects the connectivity between the prefrontal cortex and parts of the brain responsible for emotion,
resulting in overreactive and exaggerated emotional responses to positive and negative stimuli, poor
emotional self-regulation and impulsivity, and increased risk for anxiety (R. H. Berger et al., 2012; KeefeCooperman & Brady-Amoon, 2014; A. L. Miller et al., 2015; Vaughn et al., 2015). These emotional
problems can, in turn, interfere with sleep in a perpetual cycle, with increasing negative effects for young
children (Magee et al., 2014).
Nightmares and sleep terrors commonly occur in early childhood. Nightmares are anxiety-provoking
dreams whereas sleep terrors are more severe. Over the course of the evening, sleep patterns typically
shift so that rapid eye movement (REM) sleep, in which the eyes move under closed lids and the
individual dreams, increases. Deep non-REM sleep declines over the sleep period. Sleep terrors,
sometimes called night terrors, occur during deep sleep and tend to occur earlier in the evening when
periods of deep sleep are longest. Sleep terrors are most common in early childhood but may continue
into adolescence. They are often triggered by stress and anxiety. During a sleep terror the child may
scream, violently thrash around in bed, and gasp for air. The child may wake or may remain asleep and
unaware of the event. Children who experience nightmares and night terrors may dislike going to sleep.
They may develop insomnia, insist on leaving the lights on, or may cry at bedtime. Providing a consistent
sleep routine, limiting evening access to electronic screens, perhaps providing a security object such as a
stuffed animal, and providing understanding and affection can help children develop healthy sleep
habits.
Sleep is a biological necessity, but there are substantial cultural differences in sleep patterns and norms.
In one study, over 2,500 parents in Eastern (China, Hong Kong, India, Japan, Korea, Malaysia, Philippines,
Singapore, and Thailand) and Western countries (Australia/New Zealand, Canada, the United Kingdom,
and the United States) reported on their preschool-aged child’s sleep (Mindell et al., 2013). Children
from Eastern countries had later sleep times (as late as nearly 10:30 p.m. in India) compared to nearly
8:00 p.m. in Australia and New Zealand (nearly 3 hours earlier). Although all children slept about the
same amount of time over a 24-hour period, they showed different sleep patterns. Most children from
Eastern countries continued to nap during the day and shared a room or bed with other family members
at night.
Young children’s sleep patterns are influenced by cultural attitudes about the goals of childrearing.
Parents in Western countries tend to emphasize individualism. Bedtime provides opportunities for
children to learn self-regulation and independence. Young children in Western countries tend to have a
distinct presleep bedtime ritual, consisting of an organized set of activities, such as bath, dressing in
pajamas, telling stories and singing lullabies, putting the child to bed with goodnight kisses, and then
leaving the child alone in his or her room (Jenni & O’Connor, 2005). Frequently, children insist on
sleeping with a light on or taking a doll, stuffed animal, or blanket to bed with them or repeatedly call
their parents after being put to bed for various reasons such as getting a drink of water.
In many collectivist societies, such as those of many Eastern countries, the wake-to-sleep transition—
bedtime—is not recognized as a distinct event with specific activities. That is, there is no “bedtime” or
bedtime ritual. Mayan young children fall asleep when they are tired, often in someone’s arms or when
taken to bed with a family member as parents and children sleep in the same room, usually sharing a
bed (Jenni & O’Connor, 2005). Mayan parents do not report bedtime rituals—no specific sleep clothes,
stories, or songs to put young children to sleep. Mayan children typically do not use sleep aids (such as
dolls) nor do they resist sleep. Children in Bali show similar sleep habits. Balinese culture centers around
ritual and spiritual observances that often take place at night, can last throughout the night, and are
attended by children and adults (Mead, 1970). People of all ages slip in and out of sleep during the
celebrations. Balinese young children therefore learn to transition from sleep to wakefulness smoothly
and under conditions of high stimulation. They do not require bedtime rituals and can fall asleep easily
under conditions that children from other cultures might find difficult. How children (and adults) sleep—
where, with whom, and for how long—are influenced by cultural customs, but sleep is necessary to all (J.
A. Owens, 2004).
Screen Use
In 2017, smartphones were present in about 95% of homes with children under the age of 8 (up from
63% in 2013). Forty-two percent of children have their own tablet device (up from 7% in 2013) (Rideout,
2018). Children from lower-income homes and with parents with less education spend about an hour
and one-half more time on screen media than those from higher-income homes (3:39 vs. 1:50)
(Przybylski & Weinstein, 2019; Rideout, 2018). Children of color are disproportionately likely to live in
lower-income homes and are more likely to experience household chaos, which are factors associated
with increased screen use (Emond et al., 2018). Some research suggests that white children engage in
less screen time than children of color, but the difference is small (Przybylski & Weinstein, 2019).
Parents report that children tend to spend their screen time watching videos. Over two-thirds of
preschoolers watch television, videos, or DVDs each day, for about 2 hours, on average (Rideout, 2018).
Does watching television and videos influence children’s development? It depends on the program and
context. Limited screen time, watching educational programs, and co-viewing screen media with
caregivers may promote language skills (Madigan et al., 2020).
, created to simultaneously
entertain and teach children, especially those who may be unprepared for school, is a particularly
successful educational program. Young children’s learning from educational television programs is
influenced by their developing social relationships with on-screen characters, such as Ernie and Elmo
from
(Richert et al., 2011). Preschoolers who watch the show frequently display increases
in many school readiness skills, such as knowing letters and numbers as well as writing their name, earn
higher scores on standardized measures of vocabulary, view school and people of other ethnicities more
positively, and adapt better to school (Kirkorian et al., 2008). These changes are long-lasting. Young
children from low-income families who watch
and other educational programs
demonstrate better performance in reading, math, language ability, and overall school readiness 3 years
later (Wright et al., 2001).
Sesame Street
Sesame Street
Sesame Street
In contrast, noneducational programs and those created for general audiences, particularly those that
contain violence, have been associated with attention problems, motivation problems, and aggressive
behavior in early childhood and later (Barr et al., 2010). Televised violence provides models that imply
that aggression is an appropriate response to provocation and a way to obtain desired outcomes,
providing models and offering messages that aggressive behaviors and attitudes are appropriate
(Comstock & Scharrer, 1999; Slaby et al., 1995). Viewing aggression on television is associated with
aggressive behavior. The relation is small but long-lasting and consistent over many research studies
(Kirkorian et al., 2008; A. M. Moses, 2008). For these reasons, many professional organizations dedicated
to promoting the well-being of children (including the American Psychological Association [APA],
American Academy of Pediatrics [AAP], American Medical Association, and American Psychiatric
y
[
],
,
y
Association) advise parents to protect their children from violent media, including violent cartoons, the
evening news, and programs designed for general audiences (C. A. Anderson & Bushman, 2002).
Fortunately, one recent analysis of 88 current children’s shows suggested that the most popular
children’s programs were animated and tended to contain little violent content; however, they also
contained little educational and prosocial content (Taggart et al., 2019).
Although many parents and pediatricians are concerned with the effect of screen time on well-being, a
recent study suggested that there is little or no support for harmful links between digital screen use and
young children’s psychological well-being (specifically, attachment, curiosity, resilience, and positive
mood) (Przybylski & Weinstein, 2019). Limited use of computers, smartphones, and tablets is not related
to working memory and executive function in preschoolers (Jusienė et al., 2020). Screen time is
negatively associated with engaging in physical play that contributes to the growth of motor skills and
overall physical health, including weight (Fakhouri et al., 2013; Schwarzfischer et al., 2020). Greater
exposure to screens, such as a television, computer, or mobile phone in the bedroom is also associated
with fewer minutes of sleep per night in young children, which, as we discussed, may have implications
for development (Reid Chassiakos et al., 2016). Small doses of supervised screen time may permit
children to enjoy fun games and learn from educational apps while reserving time for the physical play
and activity that children require to build healthy bodies.
Illness and Toxins
Young children’s immune systems are still developing. They are more susceptible to germs and tend to
experience more frequent colds and illnesses than older children and adults. Most colds must run their
course. Preventing dehydration and treating a child’s discomfort is the appropriate treatment for a cold
and flu. Aspirin must never be administered to young children because it places children at risk to
develop Reye’s syndrome, a rare condition in which the brain and liver swell.
Immunization prevents serious, sometimes fatal diseases that were once common, such as measles. A
measles outbreak in 20 U.S. states in 2019 illustrates the value of immunization in preventing illness
(Centers for Disease Control, 2019). Measles, thought to be eliminated in the United States in 2000,
spread quickly among unvaccinated children and adults. In New York City, one child was thought to be
the source of the infection that affected over 500 other children (New York City Department of Health,
2019). Young children receive booster shots to bolster the effectiveness of vaccines received in infancy.
Many young children are exposed to toxins that can harm development. Exposure to indoor and
outdoor air pollutants, such as cigarette smoke, carbon monoxide, particulate matter, and car exhausts,
negatively affects children’s respiratory health, causes breathing problems and asthma (a chronic disease
involving the inflammation of the lungs (Goldizen et al., 2016; Landrigan et al., 2019). Peeling lead paint
can expose children to lead chips or dust that contaminates their surroundings. Lead is associated with
serious damage to the brain that can result in long-term problems in cognition, learning, and behavior,
including disorders such as attention-deficit/hyperactivty disorder (ADHD) and behavioral problems
such as delinquency in childhood, adolescence, and even adulthood (Reuben et al., 2017; Thapar et al.,
2013; Zhang et al., 2013). Although lead is no longer included as an ingredient in household paint, older
houses still contain lead paint. Children from low socioeconomic status (SES) homes are more likely to
live in older housing and be exposed to lead paint as well as other toxins that can have long-term
negative effects on children’s health and well-being (Landrigan et al., 2019; Suk et al., 2016).
Unintentional Injuries
The leading cause of death in young children is unintentional injuries and accidents. Drowning is the
most common cause of injury-related death, followed by car accidents, unintentional suffocation, and
fire (Centers for Disease Control and Prevention, 2017). The most common nonfatal injuries—accidents
that require a visit to the emergency room—are falls (Centers for Disease Control and Prevention, 2018).
A variety of individual and contextual influences place children at risk for injury. Children who are
impulsive, overactive, and difficult, as well as those diagnosed with ADHD, experience higher rates of
unintentional injuries (Acar et al., 2015; Lange et al., 2016; Morrongiello et al., 2006). Children’s risk of
injury rises when their parents report feeling little control over their behavior (Acar et al., 2015). Poor
parental and adult supervision is closely associated with childhood injury (Ablewhite et al., 2015;
Morrongiello et al., 2006). These children are more likely to test limits and protest safety restraints, such
as seat belts, wearing a helmet, or holding an adult’s hand when crossing the street. Their parents may
be less likely to intervene and prevent dangerous behavior.
Moreover, some parents hold the belief that injuries are an inevitable part of child development
(Ablewhite et al., 2015) and may therefore provide less supervision and intervention. Childhood injury is
also associated with parental distraction, such as by talking to another parent or phone use (Huynh et al.,
2017). Parents who work long hours or multiple jobs and who live in challenging environments may find
it difficult to keep tabs on their children or may feel overwhelmed.
Neighborhood disadvantage, specifically low SES and lack of resources, is associated with higher rates of
injuries, bone fractures, and injury-related death in children in the United States, Canada, and the United
Kingdom (Lyons et al., 2000; McClure et al., 2015; Rees et al., 2020; Stark et al., 2002). Disadvantaged
neighborhoods may also contribute to children’s injuries due to factors that increase overall injury risk,
such as poor surface maintenance of streets/sidewalks and poor design or maintenance of housing and
playgrounds. In addition to offering few opportunities to be active, unsafe disadvantaged
neighborhoods often offer inadequate access to sources of healthy nutrition for children; this
combination of circumstances can interfere with children developing healthy, strong bodies.
Just as there are multiple contextual factors that place children at risk of injury, there are many
opportunities for preventing and reducing childhood injuries (Schwebel, 2019). Parenting interventions
that improve supervision and monitoring, teach parents about risks to safety, and model safe practices
can help parents reduce injuries in their children (Kendrick et al., 2008). School programs can help
students learn and practice safety skills. At the community level, installing and maintaining safe
playground equipment and protected floor surfaces can reduce the injuries that accompany falls.
Disadvantaged communities may lack the funding to provide safe play spaces, placing residing children
at risk.
Thinking in Context: Applied Developmental Science
1. Identify similarities and differences in the effects of screen use in early childhood, compared with
infancy (Chapter 5). To what degree do you think similar recommendations are warranted for young
children and infants? How would you advise a parent to both an infant and preschooler?
2. Provide advice to a parent of a 4-year-old. Specifically, give four tips to parents regarding young
children’s needs for nutrition, physical activity, and sleep. Each recommendation should include
advice and an explanation of why the tip is important.
Thinking in Context: Intersectionality
All young children have the same basic health needs, but some children experience disproportionately
greater risks for poor health than their peers.
1. Discuss this statement, examining some of the health disparities associated with race, ethnicity,
and SES, on factors such as exposure to toxins, risk for illness and injuries, and other health
behaviors.
2. How do contextual factors contribute to health risks, and how can they reduce the risk for poor
health outcomes?
COGNITIVE-DEVELOPMENTAL AND SOCIOCULTURAL REASONING IN
EARLY CHILDHOOD
LEARNING OBJECTIVE
7.3 Compare Piaget’s cognitive-developmental and Vygotsky’s sociocultural perspectives on
cognitive development in early childhood.
Four-year-old Timothy stands up on his toes and releases his parachute toy, letting the action figure
dangling from a parachute drift a few feet from him and collapse on the floor. “I’m going to go up high
and make it faster,” he says, imagining standing on the sofa and making the toy sail far into the clouds.
He stands on the sofa and releases the toy, which sails a bit further this time. “Next time he’ll jump out of
the plane even higher!” Timothy thinks, excitedly. His friend Isaiah calls out, “Let’s make him land on the
moon! He can meet space people!”
Timothy and Isaiah can plan, think of solutions to problems, and use language to communicate their
ideas. They learn through play by interacting with people and objects around them. From the cognitivedevelopmental perspective, young children’s thought advances beyond the sensory and motor schemes
of infancy to include more sophisticated representational thought.
Piaget’s Cognitive-Developmental Perspective: Preoperational Reasoning
According to Piaget, preoperational reasoning appears in young children from about ages 2 to 6.
Preoperational reasoning is characterized by a dramatic leap in the use of symbolic thinking that
permits young children to use language, interact with others, and play using their own thoughts and
imaginations to guide their behavior. It is symbolic thought that enables Timothy and Isaiah to use
language to communicate their thoughts and desires—and it is also what allows them to send their toy
on a mission to the moon to visit with pretend space people.
Characteristics of Preoperational Reasoning
Young children in the preoperational stage show impressive advances in representational thinking, but
they are unable to grasp logic and cannot understand complex relationships. Children who show
preoperational reasoning tend to make several common errors, including egocentrism, animism,
centration, and irreversibility.
Egocentrism.
“See my picture?” Ricardo asks as he holds up a blank sheet of paper. Mr. Seris answers, “You can see
your picture, but I can’t. Turn your page around so that I can see your picture. There it is! It’s beautiful,”
he proclaims after Ricardo flips the piece of paper, permitting him to see his drawing. Ricardo did not
realize that even though he could see his drawing, Mr. Seris could not. Ricardo displays egocentrism, the
inability to take another person’s point of view or perspective. Egocentric children view the world from
their own perspectives, assuming that other people share their feelings, knowledge, and even physical
view of the world.
three-mountain task
A classic task used to illustrate preoperational children’s egocentrism is the
. As
shown in Figure 7.2, the child faces a table facing three large mountains. A doll is placed in a chair across
the table from the child. The child is asked how the mountains look to the doll. Piaget found that young
children in the preoperational stage demonstrated egocentrism because they described the scene from
their own perspective rather than the doll’s. They did not understand that the doll would have a different
view of the mountains (Piaget & Inhelder, 1967).
Figure 7.2 The Three-Mountains Task
Animism.
Egocentric thinking can also take the form of animism, the belief that inanimate objects are alive and
have feelings and intentions. “It’s raining because the sun is sad and it is crying,” 3-year-old Melinda
explains. Children accept their own explanations for phenomena as they are unable to consider another
viewpoint or alternative reason.
Centration.
Preoperational children exhibit centration, the tendency to focus on one part of a stimulus or situation
and exclude all others. A boy who fears that if he wears a dress he will become a girl focuses entirely on
the appearance (the dress) rather than the other characteristics that make him a boy.
Centration is illustrated by a classic task that requires the preoperational child to distinguish what
something appears to be from what it really is, the appearance–reality distinction. In a classic study
illustrating this effect, DeVries (1969) presented 3- to 6-year-old children with a cat named Maynard
(Figure 7.3). The children were permitted to pet Maynard. Then, while his head and shoulders were
hidden behind a screen (and his back and tail were still visible), a dog mask was placed onto Maynard’s
head. The children were then asked, “What kind of animal is it now?” “Does it bark or meow?” Threeyear-old children, despite Maynard’s body and tail being visible during the transformation, replied that
he was now a dog. Six-year-old children were able to distinguish Maynard’s appearance from reality and
explained that he only
like a dog.
looked
Figure 7.3 Appearance Versus Reality: Is It a Cat or Dog?
Source: De Vries (1969).
One reason that 3-year-old children fail appearance–reality tasks is because they are not yet capable of
effective dual encoding, the ability to mentally represent an object in more than one way at a time
(Flavell et al., 1986). For example, young children are not able to understand that a scale model (like a
doll house) can be both an object (something to play with) and a symbol (of an actual house)
(MacConnell & Daehler, 2004).
Irreversibility.
“You ruined it!” cried Johnson after his older sister, Monique, placed a triangular block atop the tower of
blocks he had just built. “No, I just put a triangle there to show it was the top and finish it,” she explains.
“No!” insists Johnson. “OK, I’ll take it off,” says Monique. “See? Now it’s just how you left it.” “No. It’s
ruined,” Johnson sighs. Johnson continued to be upset after his sister removed the triangular block, not
realizing that by removing the block she has restored the block structure to its original state. Young
children’s thinking is characterized by irreversibility, meaning that they do not understand that reversing
a process can often undo it and restore the original state.
Preoperational children’s irreversible thinking is illustrated by their performance on tasks that measure
conservation, the understanding that the physical quantity of a substance, such as number, mass, or
volume, remains the same even when its appearance changes (Figure 7.4). In a typical conservation of
liquids task, a child is shown two identical glasses. The same amount of liquid is poured into each glass.
After the child agrees that the two glasses contain the same amount of water, the liquid from one glass
is poured into a taller, narrower glass and the child is asked whether one glass contains more liquid than
the other. Young children in the preoperational stage reply that the taller narrower glass contains more
liquid. Why? It has a higher liquid level than the shorter, wider glass has. They center on the appearance
of the liquid without realizing that the process can be reversed by pouring the liquid back into the
shorter, wider glass. They focus on the height of the water, ignoring other aspects such as the change in
width, not understanding that it is still the same water.
Description
Figure 7.4 Additional Conservation Problems
Characteristics of preoperational children’s reasoning are summarized in Table 7.3.
Table 7.3 Characteristics of Preoperational Children’s Reasoning
Characteristic
Egocentrism
Animism
Centration
Irreversibility
Description
The inability to take another person’s point of view or perspective
The belief that inanimate objects are alive and have feelings and intentions
Tendency to focus attention on one part of a stimulus or situation and exclude all
others
Failure to understand that reversing a process can often undo a process and restore
the original state
Evaluating Preoperational Reasoning
Research with young children has suggested that Piaget’s tests of preoperational thinking
underestimated young children. Success on Piaget’s tasks appears to depend more on the child’s
language abilities than his or her actions. As we discussed earlier, to be successful at the three-mountain
task the child must not only understand how the mounds look from the other side of the table, but must
also be able to communicate that understanding. Appearance–reality tasks require not simply an
understanding of dual representation but the ability to express it. If the task is nonverbal, such as
requiring reaching for an object rather than talking about it, even 3-year-old children can distinguish
appearance from reality (Sapp et al., 2000).
Research Findings on Egocentrism and Animism.
Simple tasks demonstrate that young children are less egocentric than Piaget posited. When a 3-yearold child is shown a card that depicts a dog on one side and a cat on another, and the card is held up
between the researcher who can see the cat and the child who can see the dog, the child correctly
responds that the researcher can see the cat (Flavell et al., 1981). When the task is relevant to children’s
everyday lives (i.e., hiding) their performance suggests that they are not as egocentric as Piaget posited
(Newcombe & Huttenlocher, 1992). Other research suggests that 3- to 5-year-old children can learn
perspective-taking skills through training and retain their perspective-taking abilities 6 months later
(Mori & Cigala, 2016).
Likewise, 3-year-old children do not tend to describe inanimate objects with life-like qualities, even when
the object is a robot that can move (Jipson et al., 2016). Most 4-year-old children understand that
animals grow, and even plants grow, but objects do not (Backschneider et al., 1993). Sometimes young
children provide animistic responses. Gjersoe et al. (2015) suggest an emotional component to animistic
beliefs. They found that 3-year-olds attribute mental states to toys to which they are emotionally
attached but not to other favorite toys, even those with which they frequently engage in imaginary play.
Finally, children show individual differences in their expressions of animism and reasoning about living
things and these differences are linked with aspects of cognitive development such as memory, working
memory, and inhibition (Zaitchik et al., 2014).
Research Findings on Reversibility and the Appearance–Reality Distinction.
Although young children typically perform poorly on conservation tasks, 4-year-old children can be
taught to conserve, suggesting that children’s difficulties with reversibility and conservation tasks can be
overcome (Gallagher, 2008). In addition, making the task relevant improves children’s performance.
Asking children to play a trick on someone (i.e., “let’s pretend that this sponge is a rock and tell Anne
that it is a rock when it really is a sponge”) or to choose an object that can be used to clean spilled water,
many choose the sponge, illustrating that they can form a dual representation of the sponge as an
object that looks like a rock (Sapp et al., 2000). Three-year-old children can shift between describing the
real and fake or imagined aspects of an object or situation. In addition, they can describe misleading
appearances and functions of objects in response to natural conversational prompts, as compared with
the more formal language in the typical prompts used in traditional appearance–reality tasks (e.g., “What
is it really and truly?”) (Deák, 2006). In sum, preschoolers show an understanding of the appearance–
reality distinction and it develops throughout childhood (Woolley & Ghossainy, 2013).
Vygotsky’s Sociocultural Perspective
According to Russian psychologist Lev Vygotsky, we are embedded in a cultural context that shapes how
we think and who we become. Mental activity—cognition—is influenced by culture, specifically, the
cultural tools that members of a culture share (Robbins, 2005; Vygotsky, 1986). Cultural tools include
physical items such as computers, pencils, and paper but also ways of thinking about phenomena,
including how to approach math and scientific problems, as well as language itself. Spoken language,
the ways in which members of a culture communicate about their world, is a cultural tool that shapes
thought. Children’s lived experiences—their interactions with cultural tools and other members of their
culture—influence their views of the world and their process of thinking (Rogoff et al., 2018). Spoken
language is a cultural tool that shapes thought.
Children learn culturally valued skills by interacting with and helping skilled
partners.
Javier Mamani/Contributor/Getty Images
Children learn how to use the tools of their culture by interacting with skilled partners who provide
guidance. Suppose a child wanted to bake cookies for the first time. Rather than send the child into the
kitchen alone, we would probably accompany the child and provide the tools needed to accomplish the
task, such as the ingredients, a rolling pin to roll the dough, cookie cutters, and a baking sheet. We
would probably show the child how to use each tool, such as how to roll out the dough. With interaction
and experience, the child adopts and internalizes the tools and knowledge, becoming able to apply
them independently. That is, the child learns to bake. Vygotsky argued that in this way, culturally valued
ways of thinking and problem-solving get passed on to children.
Guided Participation and Scaffolding
As mentioned, children learn through social experience, by interacting with more experienced partners
who provide assistance in completing tasks. Children learn through guided participation (also known as
an
), a form of sensitive teaching in which partners are attuned to the needs of
children and help them accomplish more than the children could do alone (Rogoff, 2014). As novices,
children learn from more skilled, or expert, partners by observing them and asking questions. In this way,
children are apprentices, learning how others approach problems. Expert partners provide scaffolding,
assistance that is tailored to the child’s needs and permits children to bridge the gap between their
current competence level and the task at hand (Mermelshtine, 2017). Consider a child working on a
jigsaw puzzle. The child is stumped, unsure of the next step. Suppose a more skilled partner, such as an
adult, sibling, or another child who has more experience with puzzles, provides a little bit of assistance—
a scaffold. The expert partner might point to an empty space on the puzzle and encourage the child to
find a piece that fits that spot. If the child remains stumped, the partner might point out a piece or
rotate it to help the child see the relationship. The partner acts to engage the child and provides support
to help the child finish the puzzle, adjusting responses in light of the child’s emerging competence.
apprenticeship in thinking
Scaffolding occurs in formal educational settings, but also informally, any time more skilled persons
adjust their interactional style to guide children to complete a task that they could not complete alone
(Rogoff et al., 2016). Mothers vary their scaffolding behaviors in response to children’s attempts at tasks.
They spontaneously use different behaviors depending on the child’s attention skills, using more verbal
engagement, strategic questions, verbal hints, and verbal prompts when children show difficulty paying
attention during a task (Robinson et al., 2009). Moreover, maternal reading, scaffolding, and verbal
guidance are associated with 2- to 4-year-olds’ capacities for cognitive control and planning (Moriguchi,
2014). Parents and child care providers often provide this informal instruction, but anyone who is more
skilled at a given task, including older siblings and peers, can promote children’s cognitive development
(Rogoff et al., 2016). Collaboration with more skilled peers improves performance on cognitive tasks
such as card-sorting tasks, Piagetian tasks, planning, and academic tasks (Sills et al., 2016).
Zone of Proximal Development
As Vygotsky explained, “What the child can do in cooperation today, he can do alone tomorrow”
(Vygotsky, 1962, p. 104). Effective scaffolding works within the zone of proximal development, the gap
between the child's competence level—what they can accomplish independently—and what they can do
with the assistance of a skilled partner. With time, the child internalizes the scaffolding lesson and learns
to accomplish the task on their own—and their zone of proximal development shifts, as shown in Figure
7.5. Adults tend to naturally provide children with instruction within the zone of proximal development
(Rogoff, 2014). When reading a book to a child, adults tend to point to items, label and describe
characters’ emotional states, explain, ask questions, listen, and respond sensitively, helping the child
understand challenging material that is just beyond what the child can understand on their own (Silva et
al., 2014).
Description
Figure 7.5 Zone of Proximal Development
Source: Adapted from Vygotsky (1962).
The quality of scaffolding influences children’s development. In one study of preschool teachers and
children, the degree to which the adult matched the child’s needs for help in playing predicted more
autonomous play on the part of children over a 6-month period (Trawick-Smith & Dziurgot, 2011).
Adults may act intentionally to encourage and support children’s learning (Zuckerman, 2007). One study
of parents and young children visiting a science museum found that when parents provided specific
guidance in considering a conservation of volume problem—such as discussing the size of the
containers, asking “how” and “why” questions, and talking about simple math—children were more likely
to give correct responses to scientific reasoning problems, including those involving conservation
(Vandermaas-Peeler et al., 2016).
Parents' guidance acts as a scaffold within the zone of proximal development
to help children accomplish challenging tasks. Soon children become able to
complete the task independently.
Takamitsu GALALA Kato/Getty Images
Parents and preschool teachers can take advantage of the social nature of learning by assigning children
tasks that they can accomplish with some assistance, providing just enough help so that children learn
to complete the tasks independently. This helps to create learning environments that stimulate children
to complete more challenging tasks on their own (Wass & Golding, 2014). Through guided play, teachers
encourage exploration and guide children with comments encouraging them to explore, question, or
extend their interests (Bodrova & Leong, 2018).
Private Speech
As Leroy played alone in the corner of the living room, he pretended to drive his toy car up a mountain
and said to himself, “It’s a high mountain. Got to push it all the way up. Oh no! Out of gas. Now they will
have to stay here.” Young children like Leroy often talk aloud to themselves, with no apparent intent to
communicate with others. This self-talk, called private speech, accounts for 20% to 50% of the
utterances of children ages 4 to 10 (Berk, 1986). Private speech serves developmental functions. It is
thinking. Young children use self-talk to guide their own learning (Vygotsky, 1962).
Private speech plays a role in self-regulation, the ability to control one’s impulses and appropriately
direct behavior; this increases during the preschool years (Berk & Garvin, 1984). Children use private
speech to plan strategies, solve problems, and regulate themselves so that they can achieve goals.
Children are more likely to use private speech while working on challenging tasks and attempting to
solve problems, especially when they encounter obstacles or do not have adult supervision (Winsler et
al., 2009). As children grow older, they use private speech more effectively to accomplish tasks. Children
who use private speech during a challenging activity are more attentive and involved and show better
performance than children who do not (Alarcón-Rubio et al., 2014). When 4- and 5-year-old children
completed a complex multistep planning task over six sessions, those who used on-task private speech
showed dramatic improvements between consecutive sessions (Benigno et al., 2011).
Although Vygotsky considered the use of private speech a universal developmental milestone, further
research suggests that there are individual differences, with some children using private speech little or
not at all (Berk, 1992). Preschool girls tend to use more mature forms of private speech than boys. The
same is true of middle-income children as compared with low-income children (Berk, 1986). This pattern
corresponds to the children’s relative abilities in language use. Talkative children use more private
speech than do quiet children (McGonigle-Chalmers et al., 2014). Bright children tend to use private
speech earlier, and children with learning disabilities tend to continue its use later in development (Berk,
1992).
During elementary school, children’s private speech becomes a whisper or a silent moving of the lips
(Manfra & Winsler, 2006). Private speech is the child’s thinking and eventually becomes internalized as
, or word-based internal thought, a silent internal dialogue that individuals use every day to
regulate and organize their behavior (Al-Namlah et al., 2012). Inner speech plays a role in cognitive
processing, including short-term memory, planning, and executive function (Alderson-Day &
Fernyhough, 2015). Children’s use of inner speech varies with the task at hand. They are most likely to
use inner speech when completing difficult problems and tasks (Vissers et al., 2020). As the task
becomes more familiar and automatic, the accompanying inner speech declines. Inner speech is
common in adults, occurring when we use words to think to ourselves. We tend to use more inner
speech, and even private speech (talking out loud to ourselves), when completing challenging tasks,
supporting its use in self-guidance and self-regulation (Racy et al., 2020). One of the educational
implications of private speech is that parents and teachers must understand that talking to oneself or
inaudible muttering is not misbehavior but, rather, indicates an effort to complete a difficult task or selfregulate behavior.
inner speech
Evaluating Vygotsky’s Sociocultural Perspective
Although relatively unknown until recent decades, Vygotsky’s ideas about the sociocultural nature of
cognitive development have influenced prominent theories of development, such as Bronfenbrenner’s
bioecological theory (Bronfenbrenner, 1979). They have been applied in educational settings, supporting
the use of assisted discovery, guiding children’s learning, and cooperative learning with peers. Effective
instruction targets the zone of proximal development; most teachers intuitively seek to help students
grasp new concepts that are seemingly out of reach (Taber, 2020).
Similar to Piaget, Vygotsky’s theory has been criticized for a lack of precision. The mechanisms or
processes underlying the social transmission of thought are not described (Göncü & Gauvain, 2012).
Moreover, constructs such as the zone of proximal development are not easily testable (Wertsch, 1998).
In addition, underlying cognitive capacities, such as attention and memory, are not addressed. It is
understandable that Vygotsky’s theory is incomplete, as he died of tuberculosis at the age of 37. We can
only speculate about how his ideas might have evolved over a longer lifetime. Nevertheless, Vygotsky
provided a new framework for understanding development as a process of transmitting culturally valued
tools that influence how we look at the world, think, and approach problems.
Thinking in Context: Lifespan Development
What role does context take in Piaget's and Vygotsky’s theories? To what extent is cognitive
development influenced by the sociocultural contexts in which children live, according to Piaget and
Vygotsky?
Thinking in Context: Applied Developmental Science
1. Suppose that you are a preschool teacher inspired by both Piaget and Vygotsky. Which of their
ideas would you choose to incorporate into your classroom? Explain.
2. If children can be taught to respond correctly to problems assessing animism, egocentrism, or
conservation, should they? Why or why not?
INFORMATION PROCESSING IN EARLY CHILDHOOD
LEARNING OBJECTIVE
7.4 Describe information processing abilities during early childhood.
From an information processing perspective, cognitive development entails developing mental strategies
to guide one’s thinking and use one’s cognitive resources more effectively. In early childhood, children
become more efficient at attending, encoding and retrieving memories, and problem-solving.
Attention
Early childhood is accompanied by dramatic improvements in attention, particularly sustained attention,
the ability to remain focused on a stimulus for an extended period of time (Rueda, 2013). Young children
often struggle with selective attention. Selective attention refers to the ability to systematically deploy
one’s attention, focusing on relevant information and ignoring distractors. Young children do not search
thoroughly when asked to compare detailed pictures and explain what is missing from one. They have
trouble focusing on one stimulus and switching their attention to compare it with other stimuli (Hanania
& Smith, 2010). Young children who sort cards according to one dimension such as color may later be
unable to successfully switch to different sorting criteria (Honomichl & Zhe, 2011). Young children’s
selective attention at age 2.5 predicts working memory and response inhibition at age 3 (Veer et al.,
2017). The ability to selectively focus and sustain attention predicts academic skills at the beginning and
end of preschool (Shannon et al., 2021).
Working Memory and Executive Function
Young children simply get better at thinking. Recall from Chapter 5 that working memory is where all
thinking or information processing takes place. Working memory consists of a short-term store (
), a processor, and a control mechanism known as the central executive that is responsible
for executive function, directing the flow of information, and regulating cognitive activities such as
planning (Baddeley, 2016; Miyake & Friedman, 2012). Children get better at holding information in
working memory, manipulating it, inhibiting irrelevant stimuli, and planning, which allows them to set
and achieve goals (Carlson et al., 2013). With advances in executive function, children become more
skilled at controlling and deploying their cognitive resources to serve their goals (Doebel, 2020).
term memory
short-
Short-term memory is commonly assessed by a memory span task in which individuals are asked to
recall a series of unrelated items (such as numbers) presented at a rate of about 1 per second. The
greatest lifetime improvements on memory span tasks occur in early childhood. In a classic study, 2- to
3-year-old children could recall about two digits, increasing to about five items at age 7, but only
increasing another two digits, to seven, by early adulthood (Bjorklund & Myers, 2015).
With improvements in selective attention and increases in short-term memory, young children are able
to manipulate more information in working memory and become better at planning, considering the
steps needed to complete a particular act and carrying them out to achieve a goal (Plebanek & Sloutsky,
2019; Rueda, 2013). Preschoolers can create and abide by a plan to complete tasks that are familiar and
not too complex, such as systematically searching for a lost object in a yard (Wellman et al., 1979). But
they have difficulty with more complex tasks. Young children have difficulty deciding where to begin and
how to proceed to complete a task in an orderly way (Ristic & Enns, 2015). When they plan, young
children often skip important steps. One reason why young children get better at attention, memory,
and cognitive tasks is because they get better at inhibiting impulses to engage in task-irrelevant actions
and can stay focused on a task.
Improvements in executive function, working memory, and response inhibition influence how young
children understand, interact with, and respond to others. Preschool children who score high on
measures of executive function tend to show greater social competence, including more adaptive
responses to peer conflict than other children (Caporaso et al., 2019). Young children’s awareness,
understanding, expression, and regulation of emotions, known as emotional competence, are also
related to their executive function and contribute to social development (Li et al., 2020). Children who
are skilled in self-regulation tend to be better able to control their impulses and adjust to school (Savina,
2020).
Memory
Young children’s memory for events and information acquired during events, episodic memory, expands
rapidly (Roediger & Marsh, 2003; Tulving, 2002). A researcher might study episodic memory by asking a
child, “Where did you go on vacation?” or “Remember the pictures I showed you yesterday?” Most
laboratory studies of memory examine episodic memory, including memory for specific information, for
scripts, and for personal experiences.
Shana turns over one card and exclaims, “I’ve seen this one before. I know where it is!” She quickly
selects its duplicate by turning over a second card from an array of cards. Shana recognizes a card she
has seen before and recalls its location. Children’s memory for specific information, such as the location
of items, lists of words or numbers, and directions, can be studied using tasks that examine recognition
memory and recall memory. Recognition memory, the ability to recognize a stimulus one has
encountered before, is nearly perfect in 4- and 5-year-old children, but they are much less proficient in
recall memory, the ability to generate a memory of a stimulus encountered before without seeing it
again (Myers & Perlmutter, 2014).
Memory Strategies
Why do young children perform so poorly in recall tasks? Young children are not very effective at using
memory strategies, cognitive activities that make us more likely to remember (Schwartz, 2018).
Rehearsal, repeating items over and over, is a strategy that older children and adults use to recall lists of
stimuli. Children do not spontaneously and reliably apply rehearsal until after the first grade (Bjorklund
& Myers, 2015). Preschool-age children can be taught strategies, but they generally do not transfer their
learning and apply it to new tasks (Titz & Karbach, 2014). This utilization deficiency seems to occur
because of their limited working memories and difficulty inhibiting irrelevant stimuli. They cannot apply
the strategy at the same time as they have to retain both the material to be learned and the strategy to
be used. Instead, new information competes with the information the child is attempting to recall (Aslan
& Bäuml, 2010). Overall, advances in executive function, working memory, and attention predict strategy
use (Stone et al., 2016).
Young children do not always show more poor performance relative to adults. In one study, parents read
a novel rhyming verse and a word list as their 4-year-old children’s bedtime story on 10 consecutive
days. When asked to recall the verse, the 4-year-old children outperformed their parents and a set of
young adults who also listened to the verse (Király et al., 2017). The children and adults did not differ in
the ability to recall the gist of the verse. Unlike adults, young children are immersed in a culture of verse
and rely on oral transmission of information, likely underlying their skill relative to adults.
Autobiographical Memory
Autobiographical memory refers to memory of personally meaningful events that took place at a
specific time and place in one’s past (Bauer, 2015). Autobiographical memory emerges as children
become proficient in language and executive function, and develops steadily from 3 to 6 years of age
(Nieto et al., 2018). Young children report fewer memories for specific events than do older children and
adults (Baker-Ward et al., 1993; Schwartz, 2018). But by age 3 they are able to retrieve and report
specific memories, especially those that have personal significance, are repeated, or are highly stressful
(Nuttall et al. 2014). In one study, children who were at least 26 months old at the time of an accidental
injury and visit to the emergency room accurately recalled the details of these experiences even after a
2-year delay (Goodman et al., 1990). Eight-year-old children have been found to accurately remember
events that occurred when they were as young as 3½ years of age (Goodman & Aman, 1990).
Events that are unique or new, such as a trip to the circus, are better recalled; 3-year-old children will
recall them for a year or longer (Fivush et al., 1983). Frequent events tend to blur together. Young
children are better at remembering things they did than things they simply watched. For example, one
study examined 5-year-old children‘s recall of an event they observed, were told about, or experienced.
A few days later, the children who actually experienced the event were more likely to recall details in a
more accurate and organized way and to require fewer prompts (Murachver et al., 1996).
The way adults talk with the child about a shared experience can influence how well the child will
remember it (Fivush, 2019; Haden & Fivush, 1996). Parents with an elaborative conversational style
discuss new aspects of an experience, provide more information to guide a child through a mutually
rewarding conversation, and affirm the child’s responses. They may ask questions, expand children’s
responses, and help the child tell their story. Three-year-olds of parents who use an elaborative style
engage in longer conversations about events, remember more details, and tend to remember the events
g g
g
better at ages 5 and 6 (Fivush, 2011). Elaborative maternal reminiscing is associated with children’s
ability to provide more detailed personal memory, both concurrently and longitudinally (Wu & Jobson,
2019).
By age 3, children are able to retrieve and report memories of specific
experiences, especially those that have personal significance, such as a fun
day at a fair.
sarra22/Getty Images
Young children can have largely accurate memories, but they can also tell tall tales, make errors, and
succumb to misleading questions. Children’s ability to remember events can be influenced by
information and experiences that may interfere with their memories. These can include conversations
with parents and adults, exposure to media, and sometimes intentional suggestions directed at
changing the child’s view of what transpired.
Memory Suggestibility
We have seen that young children can recall much about their experiences, material that is often
relevant and accurate (Cauffman et al., 2015). Children as young as 3 years have been called upon to
relate their memories of events that they have experienced or witnessed, including abuse, maltreatment,
and domestic violence (Pantell & Committee on Psychosocial Aspects of Child and Family Health, 2017).
How suggestible are young children? Can we trust their memories?
Repeated questioning may increase suggestibility in children (La Rooy et al., 2011). In one study,
preschoolers were questioned every week about events that had either happened or not happened to
them; by the 11th week, nearly two-thirds of the children falsely reported having experienced an event
(Ceci et al., 1994). Preschool-age children may be more vulnerable to suggestion than school-age
children or adults (Brown & Lamb, 2015). When children were asked if they could remember several
events, including a fictitious instance of getting their finger caught in a mousetrap, almost none of them
initially recalled these events. After repeated suggestive questioning, more than half of 3- and 4-yearolds and two-fifths of 5- and 6-year-olds said they recalled these events—often vividly (Poole & White,
1991, 1993).
In some cases, children can resist repeated suggestion. In one study, 4- and 7-year-old children either
played games with an adult confederate (e.g., dressing up in costumes, playing tickle, being
photographed) or merely watched the games (Ceci & Bruck, 1998). Eleven days later, each child was
interviewed by an adult who included misleading questions that were often followed up with
suggestions relevant to child abuse. Even the 4-year-olds resisted the false suggestions about child
abuse. Children also vary. Some children are better able to resist social pressure and suggestive
questioning than others (Uhl et al., 2016). Children with intellectual impairments show greater
suggestibility than their non-impaired peers (Klemfuss & Olaguez, 2018).
Repeated questioning about an event that may or may not have happened
may increase suggestibility in children.
G Scammell/Alamy Stock Photo
Children are more vulnerable than adults, but adults are not entirely resistant to suggestion. Indeed,
recent research suggests that in some situations, adults are
likely than children to make quick
associations between suggestive details about unexperienced events and prior experiences, making
them more vulnerable to suggestion (Otgaar et al., 2018). Like children, adults who are exposed to
information that is misleading or inconsistent with their experiences are more likely to perform poorly
during memory interviews—and repeated questioning has a similar effect on performance (Wysman et
al., 2014).
more
Theory of Mind
Over the childhood years, thinking becomes more complex. In particular, children become increasingly
aware of the process of thinking and of their own thoughts. Theory of mind refers to children’s
awareness of their own and other people’s mental processes. This awareness of the mind can be
considered under the broader concept of metacognition, knowledge of how the mind works and the
ability to control the mind (Lockl & Schneider, 2007). Let’s explore these concepts.
Young children’s theory of mind grows and changes between the ages of 2 and 5 (Bower, 1993; Flavell et
al., 1995; Wellman, 2017). Three-year-old children understand the difference between thinking about a
cookie and having a cookie. They know that having a cookie means that one can touch, eat, or share it,
while thinking about a cookie does not permit such actions (Astington, 1993). Young children also
understand that a child who wants a cookie will be happy upon receiving one and sad upon not having
one (L. J. Moses et al., 2000). Similarly, they understand that a child who believes he is having hot
oatmeal for breakfast will be surprised upon receiving cold spaghetti (Wellman & Banerjee, 1991).
Theory of mind is commonly assessed by examining children’s abilities to understand that people can
hold different beliefs about an object or event.
Culture shapes children's thinking. Samoan and Vanuatu cultures
deemphasize internal mental states as explanations for behavior. Children are
not exposed to discussions about the mind, and they get little experience
considering other people’s thoughts.
age fotostock/Alamy Stock Photo
False Belief
Young children do not yet understand people can hold different beliefs and that some may be incorrect.
Three-year-old children tend to perform poorly on false-belief tasks, tasks that require that they
demonstrate the understanding that another person can have an incorrect belief. In a classic false-belief
task, young children are presented with a box of Band-Aids and are surprised to find that it contains
pencils rather than Band-Aids. What will other children think when they receive the Band-Aids box?
Children who have not yet developed a theory of mind will believe that other children will share their
knowledge and expect the Band-Aid box to hold pencils (Flavell, 1993). The children do not yet
understand that the other children hold different, false beliefs. In addition, young children will tend to
claim that they knew all along that the Band-Aid box contained pencils (Birch, 2005). They confuse their
present knowledge with their memories for prior knowledge and have difficulty remembering ever
having believed something that contradicts their current view (Bernstein et al., 2007).
Figure 7.6 False-Belief Task
Theory of mind, as evidenced by false-belief tasks, emerges at about 3 years of age and shifts reliably
between 3 and 4 years of age (Grosse Wiesmann et al., 2017). By age 3, children can understand that two
people can believe different things (Rakoczy et al., 2007). Four-year-old children can understand that
people who are presented with different versions of the same event develop different beliefs (Eisbach,
2004). By age 4 or 5, children become aware that they and other people can hold false beliefs (Moses et
al., 2000).
Advanced cognition is needed for children to learn abstract concepts such as belief. Performance on
false-belief tasks, such as the Band-Aid task, is associated with measures of executive function, the
abilities that enable complex cognitive functions such as planning, decision making, and goal setting
(Doenyas et al., 2018; Sabbagh et al., 2006). Advances in executive functioning facilitate children’s
abilities to reflect on and learn from experience and promote development of theory of mind (Benson et
al., 2013). One longitudinal study following children from ages 2 to 4 found that advances in executive
functioning predicted children’s performance on false-belief tasks (Hughes & Ensor, 2007). Children’s
performance on false-belief tasks is closely correlated with language development and competence in
sustaining conversations (Hughes & Devine, 2015). Preschoolers with more advanced scores on theory-
of-mind measures are more likely than their less-advanced peers to share resources and play
cooperatively with friends.
Context, Culture, and Theory of Mind
Children in many countries, including Canada, India, Thailand, Norway, China, and the United States,
show the onset and development of theory of mind between the ages of 3 and 5 (Callaghan et al., 2005;
Wellman et al., 2011). The specific pattern of theory-of-mind development varies with context and
culture. North American and Chinese children develop theory of mind in early childhood, but along
different paths (Wellman, 2017). Chinese culture emphasizes collectivism, commonality, and
interdependence among community members. Chinese parents’ comments to children tend to refer to
known and shared knowledge that community members must learn. U.S. parents emphasize Western
values such as individuality and independence. They comment more on thinking, including differences in
thoughts among individuals. U.S. children, and other children from individualist cultures, develop an
understanding of beliefs before knowledge. Chinese children tend to show the reverse pattern: an early
understanding of the knowledge aspect of theory of mind and later come to understand beliefs
(Wellman, 2017). Children from Iran and Turkey follow a similar pattern in theory-of-mind development
(Shahaeian et al., 2011).
Research with Samoan and Vanuatu children of the South Pacific confirms the relevance of culture on
theory of mind. In the South Pacific, Samoan children ages 3 to 14 years showed delayed development
in theory of mind and a prolonged transition to succeeding on theory-of-mind tasks relative to Western
samples (Dixson et al., 2018; Mayer & Träuble, 2015). Samoan and Vanuatu children’s slow progression
on theory-of-mind tasks is consistent with the Pacific Island doctrine of opacity of mind (Slaughter &
Perez-Zapata, 2014). Samoan and Vanuatu cultures deemphasize internal mental states as explanations
for behavior. Samoan and Vanuatu children, therefore, are not exposed to discussions about the mind.
They get little experience considering other people’s thoughts.
Similarly, a study of 8-year-old children from Peru used a culturally appropriate version of the Band-Aid
box task in which a sugar bowl contained tiny potatoes (Vinden, 1996). At first, the children believed the
bowl contained sugar. After learning that it contained potatoes, they answered typical false-belief
questions incorrectly, predicting that others would respond that the bowl contained potatoes. Even at
age 8, well after Western children succeed on similar tasks, the Peruvian children responded incorrectly,
unable to explain why others might initially believe that the bowl contained sugar and be surprised to
learn otherwise. One explanation is that the children in this study were raised in an isolated farming
village where farmers worked from dawn to dusk and there was no reason nor time for deception
(Vinden, 1996). The Peruvian children’s culture did not include ideas such as false belief, or deceiving
others, as their day-to-day world was concerned more with tangible activities and things rather than
considerations of people’s thoughts.
Research with English-speaking Western samples has shown that conversations about people’s thoughts
predict children’s understanding of false beliefs (Slaughter et al., 2007). Therefore, children’s success on
false-belief tasks is influenced by the beliefs held by members of their culture. In support of this idea is a
study of Pacific families living in New Zealand, in which mothers with a stronger Pacific cultural identity
referred to beliefs less often when talking to their children than mothers whose Pacific identities were
weaker (Slaughter & Perez-Zapata, 2014; Taumoepeau, 2015). Samoan and Vanuatu children may be
relatively slow to attribute false beliefs because they take longer to recognize that such beliefs exist
relative to cultures where minds are less opaque. Interestingly, Vanuatu children’s performance varied by
context. Vanuatu children who lived in towns showed more advanced performance than those who lived
in rural settings, suggesting that the social contexts within a given cultural setting also influence how
children come to understand the nature of people’s thoughts (Dixson et al., 2018).
Everyday conversations aid children in developing a theory of mind because such conversations tend to
center around and provide examples of mental states and their relation with behavior. When parents and
other adults speak with children about mental states, emotions, and behaviors, as well as discuss causes
and consequences, children develop a more sophisticated understanding of other people’s perspectives
(Devine & Hughes, 2019, 2018; Sodian et al., 2020). Children who are securely attached to a caregiver
show more advanced theory-of- mind skills than children with insecure attachments, likely because
sensitive caregivers are more responsive to children, engaging them in conversation, and fostering
emotional regulation (Szpak & Białecka‐Pikul, 2020). In addition, siblings provide young children with
opportunities for social interaction, pretend play, and practice with deception. Children with siblings
perform better on false-belief tests than do only children (McAlister & Peterson, 2013).
Children can be trained in perspective-taking. Conversation about deceptive objects (e.g., a pen that
looked like a flower) improves performance on false-belief tasks (Lohmann & Tomasello, 2003). When
children are presented with a series of deceptive objects and are shown the appearance and real states
of the objects, along with explanation, 3-year-olds showed improvements on false-belief tasks (Lohmann
& Tomasello, 2003). Discussion emphasizing the existence of a variety of possible perspectives in relation
to an object can improve performance in false-belief tasks—dialogue can facilitate the development of
theory of mind (Bernard & Deleau, 2007). When North American and European children engage in
discussion about the thoughts, beliefs, and desires of characters in stories, especially stories in which
characters play tricks to surprise or deceive one another, their performance in subsequent false-belief
tasks improves (Liu et al., 2008; Milligan et al., 2007; Slaughter & Perez-Zapata, 2014).
Metacognition
Theory of mind is a precursor to the development of metacognition (Lecce et al., 2015). Young children
know that the mind is where thinking takes place. Between 3 and 5, children come to understand that
they can know something that others do not (essential for success on false-belief tasks), that their
thoughts cannot be observed, and that there are individual differences in mental states (Pillow, 2008).
They begin to understand that someone can think of one thing while doing something else, that a
person whose eyes and ears are covered can think, and that thinking is different from talking, touching,
and knowing (Flavell et al., 1995). However, young children’s understanding of the mind is far from
complete. Three- and 4-year-old children do not understand that we think even when we are inactive.
They look for visible indicators of thinking—perhaps one reason why teachers of young children refer to
“putting on your thinking cap”—and assume their absence indicates the absence of thought. It is not
until middle childhood that children understand that the mind is always active (Flavell, 1999). Likewise,
preschoolers tend to think of the mind as simply a container for items, but older children tend to see the
mind as an active constructor of knowledge that receives, processes, and transforms information
(Chandler & Carpendale, 1998).
Young children show limited knowledge of memory functions, contributing to their poor performance
on memory tasks. Four-year-olds recognize that increasing the number of items on a list makes recall
more difficult and that longer retention intervals increase the likelihood of forgetting (Pillow, 2008). But
they know little about the effectiveness of deliberate memory strategies. Whereas 6- and 7-year-olds
demonstrated an understanding of the role of deliberate practice in memory—and practiced without
being prompted, 5-year-olds showed an understanding of deliberate practice and some capacity to
practice, but 4-year-olds showed neither of these capabilities (Brinums et al., 2018). The advances that
take place in information processing during early childhood are summarized in Table 7.4.
Table 7.4 Development of Information Processing Skills During Early Childhood
Skill
Attention
Description
Young children are better able to focus and sustain their attention to complete tasks
but have difficulty with complex tasks that require them to switch their attention
among stimuli.
Memory
Young children’s limited capacity to store and manipulate information in working
memory influences their performance on memory and problem-solving tasks. Young
children show advances in recognition memory and the ability to use scripts, but recall
memory lags behind because they are not able to effectively use memory strategies.
They often can be taught memory strategies but do not spontaneously apply them in
new situations. Episodic memory emerges in early childhood, but the extent and
quality of memories increases with age.
Theory of
Theory of mind refers to children’s awareness of their own and other people’s mental
mind
processes. When researchers use vocabulary that children are familiar with, observe
them in everyday activities, and use concrete examples and simple problems such as
those involving belief and surprise, it is clear that young children’s understanding of
the mind grows and changes between the ages of 2 and 5.
Metacognition In early childhood theory of mind, an awareness of one’s own and others’ minds
emerges. Young children demonstrate a growing ability for metacognition,
understanding the mind. Young children’s abilities are limited, and they tend to fail
false-belief and appearance–reality tasks, suggesting that their abilities to understand
the mind and predict what other people are thinking are limited.
Thinking in Context: Applied Developmental Science
1. What are the practical implications of young children’s capacities for attention and memory?
Consider specific types of memory, memory strategies, and suggestibility.
2. How can information processing theory be applied in the classroom? From an information
processing perspective, how should preschool classrooms be organized and what can teachers do
to help children learn?
Thinking in Context: Lifespan Development
1. In what ways does children’s context influence the development of theory of mind? What are
some cultural differences in theory of mind and what kinds of interactions promote the
development of theory of mind?
2. Might cultural differences in interactions relevant to theory of mind occur within the U.S.? To what
extent do you think U.S. children experience cultural and contextual differences in interactions that
might shape the development of theory of mind?
YOUNG CHILDREN’S LANGUAGE DEVELOPMENT
LEARNING OBJECTIVE
7.5 Summarize young children’s advances in language development, including dual language
learning and contextual influences on language development.
Toddlers transitioning from infancy to early childhood tend to use telegraphic speech. They learn to use
multiple elements of speech, such as plurals, adjectives, and the past tense. Children’s vocabulary and
grammar become dramatically more complex during early childhood, enabling them to communicate,
but also think, in new ways.
Vocabulary
At 2 years of age, the average child knows about 500 words; vocabulary acquisition continues at a rapid
pace. The average 3-year-old child has a vocabulary of 900 to 1,000 words. By 6 years of age, most
children have a vocabulary of about 14,000 words, which means that the average child learns a new
word every 1 to 2 hours, every day (R. E. Owens, 2020). How is language learned so quickly? Children
continue to use fast mapping (see Chapter 5) as a strategy to enable them to learn the meaning of a
new word after hearing it once or twice based on contextual association and understanding (Kucker et
al., 2015). Fast mapping improves with age.
Children learn words that they hear often, that label things and events that interest them, and that they
encounter in contexts that are meaningful to them (Ackermann et al., 2020; Mani & Ackermann, 2018).
Preschoolers can learn words from watching videos with both human and robot speakers, but they learn
more quickly in response to human speakers (Moriguchi et al., 2011), especially when the speaker
responds to them, such as through videoconferencing (e.g., Skype) (Roseberry et al., 2014). Children
learn best in interactive contexts with parents, teachers, siblings, and peers that entail turn-taking, joint
attention, and scaffolding experiences that provide hints to the meaning of new words (MacWhinney,
2015).
Another strategy that children use to increase their vocabulary is logical extension. When learning a
word, children extend it to other objects in the same category (R. E. Owens, 2020). When learning that a
dog with spots is called a Dalmatian, a child may refer to a Dalmatian bunny (a white bunny with black
spots) or a Dalmatian horse. Children tend to make words their own and apply them to all situations
they want to talk about (Behrend et al., 2001). At about age 3, children demonstrate the mutual
exclusivity assumption in learning new words: They assume that objects have only one label or name.
According to mutual exclusivity, a new word is assumed to be a label for an unfamiliar object, not a
synonym or second label for a familiar object (Markman et al., 2003). In one study, young children were
shown one familiar object and one unfamiliar object. They were told, “Show me the X” where X is a
nonsense syllable. The children reached for the unfamiliar object, suggesting that they expect new words
to label new objects rather than acting as synonyms (Markman & Wachtel, 1988). Similarly, young
children use the mutual exclusivity assumption to learn the names of parts of objects, such as the brim
of a hat, the cab of a truck, or a bird’s beak (Hansen & Markman, 2009). Four- and 5-year-old children
continue to apply the mutual exclusivity principle, but they can also understand that a given object can
have multiple labels (Kalashnikova et al., 2016).
At around 5 years of age, many children can infer the meanings of words
given the context. They can quickly understand and apply most words they
hear.
RayArt Graphics/Alamy Stock Photo
By 5 years of age, many children can quickly understand and apply most words that they hear. If a word
is used in context or explained with examples, most 5-year-olds can learn it. Preschoolers learn words by
making inferences given the context—and inferential learning is associated with better retention than
learning by direct instruction (Zosh et al., 2013). Certain classes of words are challenging for young
children. They have difficulty understanding that words that express comparisons—tall and short or high
and low—are relative in nature and are used in comparing one object to another. Thus, the context
defines their meaning, such that calling an object tall is often meant in relation to another object that is
short. Children may erroneously interpret
as referring to all tall things and therefore miss the relative
nature of the term (Ryalls, 2000). Children also have difficulty with words that express relative place and
time, such as
,
,
,
, and
. Despite these errors, children make great
advances in vocabulary, learning thousands of words each year.
here there now yesterday
tall
tomorrow
Grammar
Young children quickly learn to combine words into sentences in increasingly sophisticated ways that
follow the complex rules of grammar (de Villiers & de Villiers, 2014). Three-year-old children tend to use
plurals (cat), possessives (cat’s), and past tense (walked) (Park et al., 2012). They also tend to understand
the use of pronouns such as ,
, and
.
I you
we
a
the
Similar to telegraphic speech, young children’s sentences are short, leaving out words like and
. But
their speech is more sophisticated than telegraphic speech because they include some pronouns,
adjectives, and prepositions. Four- and 5-year-olds use four- to five-word sentences and can express
declarative, interrogative, and imperative sentences (Turnbull & Justice, 2016). Context influences the
acquisition of syntax. Four-year-old children will use more complex sentences with multiple clauses, such
as “I’m resting because I’m tired,” if their parents use such sentences (Huttenlocher et al., 2002). Parental
conversations and support for language learning are associated with faster and more correct language
use (MacWhinney, 2015). Children often use run-on sentences, in which ideas and sentences are strung
together.
“See? I goed on the slide!” called out Leona. Overregularization errors such as Leona’s are very common
in young children. They occur because young children are still learning exceptions to grammatical rules.
Overregularization errors are grammatical mistakes that young children make because they are applying
grammatical rules too stringently (R. E. Owens, 2020). For example, to create a plural noun, the rule is to
add to the word. But there are many exceptions to this rule. Overregularization is expressed when
children refer to
, and
, which illustrates that the child understands and is
applying the rules. Adult speakers find this usage awkward, but it is actually a sign of the child’s
increasing grammatical sophistication. And despite all of the common errors young children make, one
study of 3-year-olds showed that nearly three-quarters of their utterances were grammatically correct.
The most common error was in making tenses (e.g.,
) (Eisenberg et al., 2012). By the
end of the preschool years, most children use grammar rules appropriately and confidently.
s
foots, gooses, tooths
mouses
eat/eated, fall/falled
In addition to advances in vocabulary and grammar, children demonstrate a greater understanding of
the pragmatics of language, how to use language to communicate effectively (R. E. Owens, 2020). Young
children engage the people around them in conversation. They get better at turn-taking, alternating
between listening and speaking. Parents often marvel at the sophistication of their “baby’s” thoughts.
Young children carry on conversations about objects, their surroundings, and their feelings. The content
of their conversations is limited by young children’s cognitive skills, especially egocentrism. Young
children find it difficult to take another’s perspective. As children’s ability to think ahead and consider
the future improves, they can increasingly talk about things that have not yet happened, such as a trip or
party. Preschoolers recognize the need to adjust their speech to their conversational partners, such as by
speaking more simply to a toddler sibling than a peer or an adult.
Bilingual Language Learning
As we have discussed in Chapter 5, current research suggests that children who are exposed to two
languages build distinct language systems from birth (MacWhinney, 2015). The pace of learning two
languages is influenced by the degree to which the two languages differ, how often the child hears each
language, and how clearly the speakers enunciate speech sounds (Pace et al., 2021; Petitto et al., 2012;
Werker, 2012).
Typically, bilingual children have words in both languages for the same thing, which conflicts with the
mutual exclusivity assumption that characterizes most children’s vocabulary learning. A bilingual child
might say “all done” in English and “
” in Hawaiian. In contrast, monolingual children learn synonyms
pau
for words much later (Littschwager & Markman, 1994). This difference suggests that bilingual children
are aware that the words are part of two separate language systems and that a label is appropriate to a
specific language (Hoff, 2015). Bilingual children also learn two sets of rules for combining words,
grammar, and do not appear to mix the grammatical rules for the two languages. For example, bilingual
children learning French and German do not incorrectly use German words with French syntax or vice
versa (Meisel, 1989). Moreover, bilingual children tend to select the appropriate language to use with
other speakers, suggesting that they are aware that they know two languages (and that others may not)
(Genesee & Nicoladis, 2007).
The course of language development, including the pattern of vocabulary and grammatical
development in each language, tends to follow the developmental path for each language (Conboy &
Thal, 2006; Parra et al., 2011). The pace of simultaneous language learning is not the same as learning
one language. Similar to acquiring one language, the rate of acquisition for two languages depends on
the quantity and quality of the input in each language (Hoff, 2020; Hoff & Core, 2015).
Frequently, bilingual children hear one language spoken more than another; in their dominant language
they may seem similar to monolingual children in terms of development. But because children who hear
two languages will tend to hear less of either language than their monolingual peers, their rate of
growth in each language tends to be slower than those who hear and acquire a single language. That is,
a bilingual child may hear Spanish two- thirds of the time and English one-third of the time, whereas a
child learning English hears English 100% of the time. Bilingual children therefore hear less of each
language than monolingual children and tend to lag behind monolingual children in vocabulary and
grammar in each language, when measured separately (Hindman & Wasik, 2015; Hoff et al., 2012).
However, the combined vocabularies for both languages are similar in size to the vocabulary of
monolingual children; some research suggests that the total vocabulary growth in bilingual children may
be greater than that of monolinguals (Bosch & Ramon-Casas, 2014; Hoff et al., 2014). Gaps in vocabulary
and grammatical development between monolingual and bilingual children persist but narrow through
the school years, especially with continued and consistent exposure to two languages (Gathercole &
Thomas, 2009; Hoff et al., 2014).
Context and Language Development
Like all other forms of development, language is influenced by the many contexts in which children are
embedded, but especially the home. Household socioeconomic status is related to children’s language
development. Mothers with higher incomes, higher education levels, and more prestigious careers tend
to direct a greater amount of language and more diverse and complex language to their young children
than mothers of low socioeconomic status (Hart & Risley, 1995; Rowe, 2018). The quality of maternal
language input predicts children’s language development from infancy through late childhood (R. E.
Owens, 2020; Schwab & Lew-Williams, 2016). Children from low-SES backgrounds score more poorly on
standardized language measures and tests as early as 3 years of age (Golinkoff et al., 2019).
Socioeconomic Status and Language Development
A classic study of language development and SES examined a small sample of 42 children and their
mothers monthly over 2½ years, to about age 3 (Hart & Risley, 1995). The researchers measured
differences in language exposure and extrapolated their estimates to conclude that children of high SES
families encounter an average of 30 million more words in their interactions with their mothers through
age 4 than children from the lowest SES families, a difference commonly referred to as the “30 million
word gap.” In this study, SES differences in maternal language predicted vocabulary and literacy skill
years later. Therefore, the gap between children at the highest and lowest levels of SES can contribute to
lifelong differences in competency.
Recently the 30 million word gap has been come into question, largely because the estimate was based
only on language spoken directly to the child and not overhead language (Sperry et al., 2019). Children
hear a great deal of language that is not directed to them, and maternal language spoken directly to the
child is the not only speech that matters for language learning. Children who hear more language learn
more language (Hoff, 2003; Hurtado et al., 2008; Huttenlocher et al., 2010). Observations of young
children from middle-class, working-class, and poor communities revealed that, when overheard speech
is included—that is, the total number of words children hear are taken into account—the word gap
disappeared (Sperry et al., 2019). These findings suggest that SES is not related to the amount of
language children hear and its ultimate influence on language development.
Critics argue that child-directed speech is very different from overhead speech (Golinkoff et al., 2019).
While laboratory research shows that children
learn from overheard speech, it is back and forth
conversations between caregivers and children fuel language development. Moreover, the quality of
child-directed speech is a much better predictor than simply quantity of heard speech (Golinkoff et al.,
2015). The quality of maternal child-directed speech is related to SES, but there is considerable variation
within each SES group (Rowe, 2018; Schwab & Lew-Williams, 2016). Conclusions that there are never SES
differences in language environments can be harmful to disadvantaged children as it may imply that no
intervention is needed.
can
Race, Socioeconomic Status, and Language Development
Socioeconomic status, race, and ethnicity are interrelated, yet many studies fail to consider the complex
ways in which they overlap. SES is confounded with race in many studies. That is, the families from lowSES contexts also happen to be families of color, which can make it difficult to determine if a set of
findings are related to SES differences, racial and ethnic differences, or a combination of both.
Conclusions about the quality of mother–infant interactions in low-SES contexts may lead researchers to
erroneously conclude that African American mothers talk less with their young children simply because
the low-SES mothers also tended to be African American. Early studies that confounded SES and race
concluded that African American mothers speak less to their children, ask fewer questions, and elicit
lower-quality speech than other mothers (Anderson-Yockel & Haynes, 1994; Brooks-Gunn & Markman,
2005). Yet in these early studies it was impossible to determine whether maternal language was related
to SES, race, or both.
One recent study of maternal language input disentangled maternal education and race by examining
four groups of mothers: African American and non–African American mothers with a high school
education or less and African American and non–African American mothers with education beyond high
school (Vernon‐Feagans et al., 2020). In this study, maternal education accounted for differences in
maternal language input. There were no racial differences in maternal language input within each
educational level, despite large income differences between African American and non–African American
mothers within each education level. Maternal education, rather than race, may be the driver of early
maternal language input and the source of the word gap (Hindman et al., 2014; Vernon‐Feagans et al.,
2020). Interventions to help mothers promote their children’s language development emphasize childdirected speech during play and activities such as shared book reading (Dowdall et al., 2020; Hindman et
al., 2016).
Thinking in Context: Lifespan Development
1. How might advances in language development influence other domains of development, such as
cognitive or socioemotional development?
2. How might children’s everyday experiences in the home, school, and community context influence
language development? Provide examples.
3. Compare the normative changes in vocabulary and grammar for young children learning one
language with those learning two languages. Do you think language development unfold in similar
ways for monolingual and bilingual language learners? Why or why not?
Thinking in Context: Intersectionality
1. From an intersectional perspective, race and ethnicity, education, and poverty intersect with
power, including dominant beliefs about what is normative and what kinds of family interactions are
preferred. Considering intersectionality, why do some researchers question the 30 million word gap?
2. Given recent findings illustrating the interactive influence of race and SES on young children’s
language development, what interventions do you suggest to help young children and their
parents? Why do we see these patterns, what might influence them, and what can we do to help
young children?
EARLY CHILDHOOD EDUCATION
LEARNING OBJECTIVE
7.6 Identify and explain various approaches to early childhood education.
Many children attend kindergarten prior to entering elementary school, but only 15 states require
children to complete kindergarten (Education Commission of the States, 2014). Early education is
important for children’s cognitive, social, and emotional development. Preschool programs provide
educational experiences for children ages 2 to 5.
Child-Centered and Academically Centered Preschool Programs
There are two general approaches to early childhood education. Academically centered preschool
programs emphasize providing children with structured learning environments in which teachers deliver
direct instruction on letters, numbers, shapes, and academic skills. Child-centered preschool programs
take a constructivist approach that encourages children to actively build their own understanding of the
world through observing, interacting with objects and people, and engaging in a variety of activities that
allow them to manipulate materials and interact with teachers and peers (Kostelnik et al., 2015). Children
learn by doing, through play, and learn to problem-solve, get along with others, communicate, and selfregulate.
Montessori schools, first created in the early 1900s by the Italian physician and educator Maria
Montessori (1870–1952), exemplify the child-centered approach, in which children are viewed as active
constructors of their own development and are given freedom in choosing their activities (Lillard, 2021).
Teachers act as facilitators, providing a range of activities and materials, demonstrating ways of exploring
them, and providing help when the child asks. The Montessori approach is credited with fostering
independence, self-regulation, and cognitive and problem-solving skills (Ackerman, 2019).
In this Montessori classroom, children explore and play together.
Laura Dwight/Alamy Stock Photo
In contrast, problems have been documented with teacher-directed rigid academic programs. Children
immersed in such programs sometimes show signs of stress such as rocking, may have less confidence
in their skills, and may avoid challenging tasks compared with children who are immersed in more active
forms of play-based learning (Stipek et al., 1995). Such programs are also negatively associated with
reading skills in first grade (Lerkkanen et al., 2016).
Instead of a purely academic approach, many practitioners advocate for a developmentally appropriate
practice, which tailors instruction to the age of the child, recognizing individual differences and the need
for hands-on active teaching methods (Kostelnik et al., 2015). Teachers provide educational support in
the form of learning goals, instructional support, and feedback, but they also emphasize emotional
support and help children learn to manage their own behavior (S. Anderson & Phillips, 2017). Moreover,
teachers are provided with explicit instruction in how to teach and the teaching strategies needed to
support young children’s literacy, language, math, social, and self-regulatory development (Markowitz et
al., 2018). Responsive child-centered teaching is associated with higher reading and math scores during
first grade (Lerkkanen et al., 2016).
Effective early childhood educational practice is influenced by cultural values (Gordon & Browne, 2016).
In the United States, a society that emphasizes individuality, a child-centered approach in which children
are given freedom of choice is associated with the most positive outcomes (Marcon, 1999). Yet in Japan,
the most effective preschools tend to foster collectivist values and are society centered, with an
emphasis on social and classroom routines, skills, and promoting group harmony (Holloway, 1999;
Nagayama & Gilliard, 2005). Japanese preschools prepare children for their roles in society and provide
formal instruction in academic areas as well as art, swordsmanship, gymnastics, tea ceremonies, and
Japanese dance. Much instruction is teacher directed, and children are instructed to sit, observe, and
listen. Teachers are warm but address the group as a whole rather than individuals. This structured
approach is associated with positive outcomes in Japanese children (Holloway, 1999; Nagayama &
Gilliard, 2005), illustrating the role of culture in influencing outcomes of early childhood education. Even
within a given country such as the United States, there exist many ethnicities and corresponding
cultures, such as those of Native Americans and Mexican Americans. In each case, instruction that is
informed by an understanding of children’s home and community culture fosters a sense of academic
belongingness that ultimately influences academic achievement (Gilliard & Moore, 2007; Gordon &
Browne, 2016).
Early Childhood Education Interventions
Recognizing that young children’s developmental needs extend beyond education, one of the most
successful early childhood education and intervention programs in the United States, Project Head Start,
was created by the federal government to provide economically disadvantaged children with nutritional,
health, and educational services during their early childhood years, prior to kindergarten (Ramey &
Ramey, 1998). Parents of Head Start children also receive assistance, such as education about child
development, vocational services, and programs addressing their emotional and social needs (Zigler &
Styfco, 2004).
Over the past four decades, a great deal of research has been conducted on the effectiveness of Head
Start. The most common finding is that Head Start improves cognitive performance, with gains in IQ and
achievement scores in elementary school (Zhai et al., 2011). Compared with children who do not
participate in Head Start, those who do so have greater parental involvement in school, show higher
math achievement scores in middle school, are less likely to be held back a grade or have problems with
chronic absenteeism in middle school, and are more likely to graduate from high school (Duncan et al.,
2007; Joo, 2010; Phillips et al., 2016). Head Start is associated with other long-lasting social and physical
effects, such as gains in social competence and health-related outcomes, including immunizations
(Huston, 2008). Yet some research has suggested that the cognitive effects of Head Start may fade over
time such that, by late childhood, Head Start participants perform similarly to control group low
socioeconomic status children who have not participated in Head Start (U.S. Department of Health and
Human Services, & Administration for Children and Families, 2010). Early intervention may not
compensate for the pervasive and long-lasting effects of poverty-stricken neighborhoods and
inadequate public schools (Schnur & Belanger, 2000; Welshman, 2010). At the same time, long-term
advantageous effects of attending Head Start include higher graduation rates and lower rates of
adolescent pregnancy and criminality for low-income children who attend Head Start compared with
their control group peers (Duncan & Magnuson, 2013). Despite these findings, only about one-third of
poor children are enrolled in Head Start, and this proportion has shrunk over the past decade, as shown
in Figure 7.7.
Description
Figure 7.7 Number of Children (in Thousands) Enrolled in Head Start and
Early Head Start, and Children Enrolled as a Percentage of Children in Poverty,
2006–2014
Source: Child Trends Databank (2015).
Additional evidence for the effectiveness of early childhood education interventions comes from the
Carolina Abecedarian Project and the Perry Preschool Project, carried out in the 1960s and 1970s. Both
of these programs enrolled children from families with incomes below the poverty line and emphasized
the provision of stimulating preschool experiences to promote motor, language, and social skills as well
as cognitive skills, including literacy and math. Special emphasis was placed on rich, responsive adult–
child verbal communication as well as nutrition and health services from birth to school age. Children in
these programs achieved higher reading and math scores in elementary school than their nonenrolled
peers (Campbell & Ramey, 1994). As adolescents, they showed higher rates of high school graduation
and college enrollment, as well as lower rates of substance abuse and pregnancy (Campbell et al., 2002;
Muennig et al., 2011). At ages 30 and 40, early intervention participants showed higher levels of
education and income (Campbell et al., 2012; Schweinhart et al., 2005). Researchers continue to study
and apply the Abecedarian approach today in playgroups, preschools, and other settings (Page et al.,
2019; Sparling & Meunier, 2019).
The success of early education intervention programs has influenced a movement in the United States
toward comprehensive prekindergarten (pre-K). Young children who participate in high-quality pre-K
programs enter school with greater readiness to learn and score higher on reading and math tests than
their peers (Gormley et al., 2010). Although all young children appear to benefit from pre-K, children
from low-income homes benefit the most (Slicker & Hustedt, 2019).
Children who attend Head Start programs have early educational experiences
that improve cognitive and social skills and prepare them for kindergarten
and elementary school.
Laura Dwight/Alamy Stock Photo
During 2017–2018, 44 states provided preschool programs (Friedman-Krauss et al., 2019). However, not
all children in these states had access to preschool. Rates of enrollment of 3- and 4-year-olds ranged
from a high of 69% of children in Vermont to 5% or less in 11 states. A few states, including Oklahoma,
Vermont, and Florida, provide universal access to pre-K to all children, and many more states are moving
in this direction (Williams, 2015). Beginning in the fall of 2017, New York City initiated a city-funded “3-K
for all” program of free full-day preschool to all 3-year-olds (K. Taylor, 2017). Although some research
suggests that half-day and more intense full-day programs do not differ in academic and social
outcomes, full-day preschool incorporates the benefit of free child care to working parents that is likely
of higher quality than they might have otherwise been able to afford (Leow & Wen, 2017). Funding
public preschool programs is daunting, but the potential rewards are tremendous.
Thinking in Context: Applied Developmental Science
What are the pros and cons of academically centered and child-centered preschool programs? Design a
preschool setting and program that combines aspects of both types of programs, as you see fit. Discuss
your choices.
Thinking in Context: Lifespan Development
Consider early childhood interventions such as Head Start from the perspective of Bronfenbrenner’s
bioecological systems theory. Identify individual and contextual factors at the microsystem, mesosystem,
and exosystem that programs may address to promote children’s development. What role might
macrosystem factors play in such interventions?
APPLY YOUR KNOWLEDGE
Researchers who study deception in children must find unique ways of determining when young
children are capable of lying. In one study (Saarni, 1984), children were given a desirable toy and
promised that they would receive another. Instead, they received an undesirable gift that was not a toy.
The child’s facial expressions, nonverbal behavior, and emotional displays were recorded. The
researchers were interested in when children would begin to mask their feelings and lie about the
desirability of the gift. In another study (Lewis et al., 1989), young children were left alone in a laboratory
environment, told by the researcher not to peek at a toy in the researcher’s absence, and later
questioned about whether they had peeked at the toy. Other studies (Polak & Harris, 1999) entailed the
researcher telling children not to touch the toy and later questioning them about whether they had
touched the toy in the researcher’s absence.
1.
2.
3.
4.
How does cognitive development influence children’s ability to deceive?
What emotional capacities does lying require?
When would you expect young children to become capable of lying? Why?
What are ethical issues entailed in research on deception in children? How might considerations of
children’s feelings of guilt, shame, or frustration and their developing capacities for self-regulation
inform this question?
CHAPTER SUMMARY
7.1
Discuss physical growth, including motor and brain development, in early childhood.
During early childhood, growth slows relative to infancy, bones begin to ossify, and body
proportions change as young children gain muscle and become more lean. Advances in gross
motor skill permit young children to balance and coordinate their bodies and engage in more
complicated physical activities, such as throwing and catching balls. As children’s fine motor skills
improve they learn to write and engage in self-care activities such as buttoning a shirt.
Synaptogenesis, pruning, myelination, and lateralization continue in early childhood and contribute
to enhanced plasticity.
7.2
Examine the influence of nutrition, physical activity, sleep, and screen use on young children’s
health as well as risks to health.
Most children in developed nations eat enough calories, but their diets are often insufficient in
vitamins and minerals. Physical activity enhances growth and is consistently associated with
advances in motor development, fitness, and bone and skeletal health. Time spent outdoors and
access to safe play environments are associated with greater physical activity. Sleep problems pose
risks to young children’s development, such as cognitive difficulties, including problems with
attention, working memory, and slower processing speed. Screen time may adversely affect young
children’s health through its inverse relationship with physical activity and sleep quality. Young
children tend to experience more colds and illnesses than older children. Exposure to toxins can
harm children’s physical and cognitive development. Unintentional injuries, accidents, are the
leading cause of death in young children but many can be prevented by addressing the contextual
factors that may place children at risk for injury.
7.3
Compare Piaget’s cognitive-developmental and Vygotsky’s sociocultural perspectives on
cognitive development in early childhood.
Piaget explained that children in the preoperational stage of reasoning are able to think using
mental symbols, but their thinking is limited because they cannot grasp logic. Simplified and
nonverbal tasks demonstrate that young children are more cognitively advanced and less
egocentric than Piaget posed. From Vygotsky’s sociocultural perspective, children’s learning occurs
through guided participation, scaffolding within the zone of proximal development. With time, the
child internalizes the lesson and learns to accomplish the task on his or her own. In this way,
cognitive development entails actively internalizing the tools of our culture.
7.4
Describe information processing abilities during early childhood.
The ability to sustain attention improves in early childhood through the preschool years. Episodic
memory also improves steadily, but young children’s limited working memory makes it difficult for
them to use memory strategies. Autobiographical memory develops steadily and is accompanied by
increases in the length, richness, and complexity of recall memory. Advances in theory of mind
enable children to understand that people can believe different things, that beliefs can be
inaccurate, and that sometimes people act on the basis of false beliefs. Children thereby become
able to lie or use deception in play.
7.5
Summarize young children’s advances in language development, including dual language
learning and contextual influences on language development.
Young children apply strategies such as logical extension and the mutual exclusivity assumption to
increase their vocabulary rapidly. Young children quickly move from telegraphic speech to
y p y
g
q
y
g p
p
combining words into sentences in increasingly sophisticated ways—using multiple elements of
speech, such as plurals, adjectives, and the past tense—yet they often make overregularization
errors. Parental conversations and support for language learning are associated with faster and
more correct language use. At the end of the preschool years, most children use many grammar
rules appropriately and confidently. Children who are exposed to two languages build two distinct
systems with similar patterns of development. The rate of acquisition for two languages depends on
the quantity and quality of the input in each language. When considering one language, bilingual
children tend to show a gap in vocabulary compared to their monolingual peers; however, when
both languages are considered the gap closes. Contextual factors, such as parental education and
SES, contribute to language development.
7.6
Identify and explain various approaches to early childhood education.
Child-centered preschool programs encourage children to manipulate materials, interact with
teachers and peers, and learn by doing, through play. Academically oriented preschool programs
provide children with structured learning environments through which they learn letters, numbers,
shapes, and academic skills via drills and formal lessons. Head Start and other early childhood
education interventions can promote children’s learning and development.
Key Terms
Academically centered preschool programs
Animism
Appearance–reality distinction
Autobiographical memory
Centration
Child-centered preschool
Conservation
Developmentally appropriate practice
Egocentrism
Episodic memory
False-belief tasks
Guided participation
Irreversibility
Lateralization
Logical extension
Memory strategies
Metacognition
Montessori schools
Mutual exclusivity assumption
Nightmares
g
Ossification
Overregularization errors
Plasticity
Preoperational reasoning
Private speech
Project Head Start
Recall memory
Recognition memory
Scaffolding
Scripts
Selective attention
Sleep terrors
Sustained attention
Theory of mind
Three-mountain task
Zone of proximal development
Descriptions of Images and Figures
Back to Figure
Additional Conservation Problems includes conservation task, original presentation and transformation
which are placed in three columns. The first column, ’Conservation task’ includes number, mass and
liquid. Under the second column ’Original presentation’, the text in first row reads as ’Are there the same
number of pennies in each row?’. 12 pennies in 2 rows, 6 in each row are shown below the text; the text
in second row reads as ’Is there the same amount of clay in each ball?’. 2 clay balls are shown below the
text; the text in third row reads as ’Is there the same amount of water in each glass?’. 2 glasses with
water are shown below the text. Under the third column ’Transformation’, the text in first row reads as
’Now are there the same number of pennies in each row, or does one row have more?’. 12 pennies in 2
rows, 6 in each row, one is arranged with more spaces and other with less space are shown below the
text; the text in third row reads as ’Now does each piece have the same amount of clay, or does one
have more?’. 1 clay ball and a piece of item with clay and are shown below the text; the text in third row
reads as ’Now does each glass have the same amount of water, or does one have more?’. 1 glass with
water and a glass of water is pouring into a bowl are shown below the text.
Back to Figure
The horizontal axis represents “Level of competence” and the vertical axis represents “Level of
challenge.” An elongated hexagon placed diagonally at the center of the graph reads “Zone of Proximal
Development.” At the top, an arrow points to the text “What the learner can achieve with scaffolding”
and at the bottom, an arrow points to the text “What the learner can currently achieve independently.”
Back to Figure
The horizontal axis represents years from 2006 to 2013 and the vertical axis represents the number
enrolled (in thousands) ranging from 0 to 1200 in increments of 200. The lines represent Head Start
(number), Early Head Start (number), Head Start (percent) and Early Head Start (percent). The data from
the graph are shown in the table below.
Year
2006
2007
2008
2009
2010
2011
2012
2013
Head Start Early Head Start Head Start Early Head Start
(number)
(number)
(percent)
(percent)
975
976
964
984
993
979
85
2.5
84
120
149
151
42.0
39.5
38.1
33.3
32.9
32.2
916
145
34.3
4.1
2.3
3.0
3.6
3.8
8 SOCIOEMOTIONAL DEVELOPMENT IN EARLY
CHILDHOOD
FluxFactory/Getty Images
“Oww!” Logan cried out as he tripped. “Are you OK?” asked his mother. Logan nodded, “I’m OK but I
don’t like that step.” “I agree,” smiled Logan’s mother, marveling at how Logan has matured. Just a short
while ago he would react to frustration by crying. Now he used words to express his wants and needs, at
least most of the time. Early childhood is a time of transition from the dependence of infancy and
toddlerhood to the increasing capacities for autonomy and emotional regulation characteristic of
childhood. How do young children learn to understand and control their emotions? Do they experience
the same complex emotions that older children and adolescents experience? What is the role of parents
in children’s emotional and social development? What is the function of play in development? In this
chapter, we explore children’s experience and understanding of their social and emotional world and
how socioemotional development changes over the early childhood years.
EMERGING SENSE OF SELF
LEARNING OBJECTIVE
8.1 Describe young children’s sense of initiative, self-concept, and self-esteem.
When assigned a task, such as dusting off a bookcase shelf, 3-year-old Shawna calls out, “I’ll do it!” After
completing the task, she proudly proclaims, “I did it!” The autonomy that Shawna developed during the
toddler years has prepared her to master the psychosocial task of the preschool years: developing a
sense of initiative (Erikson, 1950).
Psychosocial Development in Early Childhood
During Erikson’s third psychosocial stage, initiative versus guilt, young children develop a sense of
purpose and take pride in their accomplishments. As they develop a sense of initiative, young children
make plans, tackle new tasks, set goals (e.g., climbing a tree, writing their name, counting to 10), and
p
g
g
g
g
g
work to achieve them, persisting enthusiastically in tasks, whether physical or social, even when
frustrated (Lambert & Kelley, 2011).
Much of the work of this stage occurs through play. During play, young children experiment and practice
new skills in a safe context and learn to work cooperatively with other children to achieve common goals
(Syed & McLean, 2018). Children in all societies practice adult roles in play, such as mother, father,
doctor, teacher, and police officer (Gaskins, 2014). Hopi Indian children pretend to be hunters and
potters, and the Baka of West Africa pretend to be hut builders and spear makers (Roopnarine et al.,
1998). The sense of pride that children feel from accomplishment fuels their play and fosters curiosity.
Children become motivated to concentrate, persist, and try new experiences, such as climbing to the top
of the big kid slide—and sliding down by themselves. Through play, children also learn how to manage
their emotions and develop self-regulation skills (Goldstein & Lerner, 2018).
During early childhood, children come to identify with their parents and internalize parental rules
(Paulus, 2020). Young children feel guilt when they fail to uphold rules and when they fail to achieve a
goal. If parents are controlling—not permitting children to carry out their sense of purpose—or are
highly punitive, critical, or threatening, children may not develop high standards and the initiative to
meet them (Mounts & Allen, 2019). Instead, children may be paralyzed by guilt and worry about their
inability to measure up to parental expectations. They may develop an overly critical conscience and be
less motivated to exert the effort to master new tasks.
Participating in household work is one way in which children develop
initiative, a sense of purpose, and pride in their accomplishments.
iStock/Rawpixel
Children who develop a sense of initiative demonstrate independence and act purposefully. Their
success in taking initiative and the feeling of competence and pride that accompanies it contributes to
young children’s developing sense of self.
Self-Concept
Three- and 4-year-old children tend to understand and describe themselves concretely, using observable
descriptors including appearance, general abilities, favorite activities, possessions, and simple
psychological traits (Harter, 2012). Ryder explains, “I’m 4 years old. I have black hair. I’m happy, my
doggie is white, and I have a television in my room. I can run really fast. Watch me!” Ryder’s selfdescription, his self-concept, is typical of children his age. Soon children begin to include emotions and
attitudes in their self-descriptions, such as “I’m sad when my friends can’t play,” suggesting an emerging
awareness of their internal characteristics (Thompson & Virmani, 2010).
Children naturally notice physical differences in themselves and others associated with race, such as skin
color and hair color and texture. Three- and 4-year-old white children tend to express racial preferences
in the form of a pro-white bias (Perszyk et al., 2019; Williams & Steele, 2019). Young children of color
may also demonstrate preferences for lighter skin or internalize racial biases (Jordan & Hernandez-Reif,
2009; Kaufman & Wiese, 2012). Bias declines dramatically in late childhood, about age 9 (Aboud &
Steele, 2017; Williams & Steele, 2019). Why does it occur? Young children are immersed in a world that
sends messages about the characteristics and acceptability of skin color. Although research is just
beginning to examine how information about race and racial preferences influences young children’s
sense of self, it is likely that young children internalize race-related messages into their early
understanding of self. Without awareness, parents often communicate racial biases to children (Pirchio
et al., 2018). Adults also tend to delay conversations about race because they underestimate children’s
understanding and processing of race (Sullivan et al., 2020). Parents and teachers can counter
discriminatory messages by adopting an anti-bias framework that includes learning about race through
storybook reading and discussion (Beneke et al., 2019).
Children’s conceptions of themselves are influenced by their interactions with parents and the cultural
context in which they are raised. In one study, preschool through second-grade U.S. and Chinese
children were asked to recount autobiographical events and describe themselves in response to openended questions (Wang, 2004). The U.S. children often provided detailed accounts of their experiences.
They focused on their own roles, preferences, and feelings and described their personal attributes and
inner traits positively. In contrast, Chinese children provided relatively skeletal accounts of past
experiences and focused on social interactions and daily routines. They often described themselves in
neutral or modest tones, referring to social roles and context-specific personal characteristics. These
differences are consistent with cultural values of independence in the United States and collectivism in
China. In another study, U.S. preschool children reported feeling more sadness and shame in response to
failure and more pride in response to success than did Japanese preschool children (Lewis et al., 2010).
The Japanese preschool children displayed few negative emotions in response to failure but showed
self-conscious embarrassment in response to success. Culture influences how children come to define
and understand themselves and even the emotions with which they self-identify (Thompson & Virmani,
2010).
Self-Esteem
Young children tend to evaluate themselves positively. That is, they generally have a high sense of selfesteem. Three-year-old Dorian exclaims, “I’m the smartest! I know all my ABCs! Listen! A, B, C, F, G, L, M!”
Like Dorian, many young children are excited but also unrealistically positive about their abilities,
underestimating the difficulty of tasks and believing that they will always be successful (Harter, 2012).
Preschoolers often fail to recognize deficits in their abilities and tend to view their performance
favorably, even when it is not up to par (Boseovski, 2010). Even after failing at a task several times, they
often continue to believe that the next try will bring success.
Young children’s overly optimistic perspective on their skills can be attributed to their cognitive
development, secure attachment with caregivers, and the overwhelmingly positive feedback they usually
receive when they attempt a task (Goodvin et al., 2008; Verschueren, 2020). These unrealistically positive
expectations serve a developmental purpose: They contribute to young children’s growing sense of
initiative and aid them in learning new skills. Young children maintain their positive views about
themselves because they do not yet engage in social comparison. In other words, they do not compare
their performance with that of other children. With advances in cognition and social experience, children
begin to learn their relative strengths and weaknesses, and their self-evaluations become more realistic
(Rochat, 2013). Between ages 4 and 7, children’s self-evaluations become linked with their performance.
In one study, children’s self-evaluations declined when they failed tasks assigned by an adult as well as
those they perceived as important (Cimpian et al., 2017). Sensitive parenting that supports children’s
attempts at difficult tasks emphasizes the value of effort and helps children identify and take pride in
success that promotes self-esteem.
Thinking in Context: Lifespan Development
1. In what ways might young children’s inaccurate views of themselves and their abilities be
adaptive? Is there a benefit to having an overoptimistic view in early childhood?
2. How might young children’s views of themselves influence their ability to tackle the psychosocial
task of this stage, developing a sense of initiative?
3. How does a growing sense of initiative help children? How might it influence their behavior at
home, school, and with peers?
EMOTIONAL DEVELOPMENT IN EARLY CHILDHOOD
LEARNING OBJECTIVE
8.2 Discuss the development of emotional understanding, regulation, and empathy in early
childhood.
Young children’s advances in cognitive development and growing sense of self influence the emotions
they show and the contexts in which they display these emotions. Moreover, young children come to
understand people and social relationships in more complex ways, leading to new opportunities for
emotional development. Emotional development includes an increasing awareness and management of
emotion, as well as an ability to recognize others’ emotions and infer causes and consequences of
others’ emotions (Camras & Halberstadt, 2017).
Emotional Understanding
Donald begins to cry as his mother leaves, dropping him off at preschool. Watching Donald, Amber
explains to her mother, “Donald is sad because he misses his mommy,” and she brings Donald a toy.
“Don’t be sad,” she says. By 3 to 4 years of age, children recognize and name emotions based on their
expressive cues. By age 4, children begin to understand that external factors (such as losing a toy) can
affect emotion and can predict a peer’s emotion and behavior (such as feeling sad and crying or feeling
angry and hitting things) (Goodvin et al., 2015).
The emergence of theory of mind has profound implications for emotional development. As children
begin to take other people’s perspectives, they can apply their understanding of emotions to understand
and help others, such as recognizing that a sibling is sad and offering a hug. Children’s growing
understanding of the mind leads them to appreciate the role of internal factors, such as desires, on
emotion and behavior (Wellman, 2017). By age 5, most children understand that desire can motivate
emotion, and many understand that people’s emotional reactions to an event can vary based on their
desires.
Theory of mind influences the development and expression of self-conscious emotions, such as pride
and guilt. Self-conscious emotions emerge as children become aware of rules and standards that define
socially appropriate behavior and that others have expectations for their behavior (Muris & Meesters,
2014). In response to success, children’s joy may be accompanied by the self-conscious emotion of
pride. Likewise, shame results from recognizing that poor outcomes are the result of their behavior.
Children’s interactions with siblings offer important opportunities to practice identifying emotions,
decoding the causes of emotions, anticipating the emotional responses of others, and using their
emotional understanding to influence their relationships and affect the behavior of others (Kramer,
2014). Young children also often enact emotions in pretend sociodramatic play, providing experience
and practice in understanding emotions and their influence on social interactions (Goodvin et al., 2015).
Pretend play with siblings and peers gives children practice in acting out feelings, considering others’
perspectives, and implementing self-control, regulating aggression, and improving the children’s
understanding of emotion (Hoffmann & Russ, 2012; Laurent et al., 2018). Sociodramatic play is
associated with emotional control in preschoolers and predicts predicted their expressiveness,
knowledge, and emotional control one year later (Goldstein & Lerner, 2018; Lindsey & Colwell, 2013).
Interactions with caregivers also plays a role in advancing children’s understanding of emotions. When
parents talk to their preschoolers about emotions and explain their own and their children’s emotions,
the children are better able to evaluate and label others’ emotions and show better adjustment, as rated
by teachers (Camras & Halberstadt, 2017; Thompson et al., 2020). The preschool classroom offers many
opportunities for children to learn about emotions through play, modeling, and direct instruction
(Valiente et al., 2020). Book-reading—accompanied by dialogue about the characters, their emotions,
and their motivations—can help advance preschoolers’ emotional understanding (Pons et al., 2019;
Schapira & Aram, 2020). Preschool teachers also engage in emotion coaching, helping young children to
understand the emotions they feel and see in others (Silkenbeumer et al., 2018; Yelinek & Grady, 2019).
Emotion Regulation
Over the course of childhood, children make great strides in regulating their emotions and become
better able to manage how they experience and display emotions. Advances in emotion regulation are
influenced by cognition, executive function, theory of mind, and language development. By age 4,
children can explain simple strategies for reducing emotional arousal, such as limiting sensory input
(covering their eyes), talking to themselves (“It’s not scary”), or changing their goals (“I want to play
blocks,” after having been excluded by children who were playing another game) (Thompson &
Goodvin, 2007). Emotion regulation strategies are a response to emotions, change with age, and also
influence children’s emotional experience (Eisenberg et al., 2015).
Skills in emotion regulation are associated with social competence and overall adjustment (Deneault &
Ricard, 2013). Emotional regulation plays a key role in children’s ability to adapt to their environment,
including the novel demands of the school setting (Harrington et al., 2020). Children who are able to
direct their attention and distract themselves when distressed or frustrated become well-behaved
students and are well-liked by peers (McClelland & Cameron, 2011).
Parents are important resources for emotional management in early childhood. Mothers’ emotional
awareness and management skills influence children’s emotional regulation skills (Crespo et al., 2017).
Parents who are responsive when children are distressed, who frame experiences for children (e.g., by
acting cheery during a trip to the doctor), and who explain expectations and strategies for emotional
management both model and foster emotion regulation (Sala et al., 2014). In contrast, dismissive or
hostile reactions to children’s emotions prevent them from learning how to manage and not be
overwhelmed by their emotions (Zeman et al., 2013).
Empathy
In early childhood, young children develop the cognitive and language skills that permit them to reflect
on emotions, talk about emotions, and convey feelings of empathy, the ability to understand someone’s
feelings (Main & Kho, 2020; Stern & Cassidy, 2018). Empathy is linked with the perspective-taking ability
that emerges with theory of mind. The child must imagine another’s perspective in order to understand
how that person feels (Eisenberg et al., 2015). A secure attachment to a caregiver helps children develop
the emotional understanding and regulation skills on which empathy depends (Ştefan & Avram, 2018).
Parents who provide supportive and compassionate responses to children’s emotions foster the
development of empathy in children (Hu et al., 2020).
Empathy influences how young children make judgments in their social world. Children who score
higher on measures of empathy tend to rate moral transgressions involving physical and psychological
harm as more serious and are more likely to rate unfairness as more deserving of punishment than other
children (Ball et al., 2017). Empathy develops over early childhood. Three-year-old children protest when
an agent responds to a hurt child by laughing, but not when the agent ignores the hurt child; but 5year-old children rate
the antisocial agent and the agent that ignored the needy child negatively
(Paulus et al., 2020). Children who feel empathy for another person often are primed to engage in
prosocial behavior, voluntary behavior intended to benefit another, as discussed later in this chapter
(Eisenberg et al., 2015).
both
Thinking in Context: Lifespan Development
Cognitive development influences how young children understand and regulate their emotions, as well
as their capacity for empathy. Examine these interrelations, especially the role of theory of mind in young
children’s emotional experience.
Thinking in Context: Applied Developmental Science
How can we help children learn strategies for self-control? Provide suggestions for how parents, child
care providers, and preschool teachers can help children understand and learn to regulate their
emotions.
MORAL DEVELOPMENT AND BEHAVIOR IN EARLY CHILDHOOD
LEARNING OBJECTIVE
8.3 Summarize perspectives on moral development and behavior, including prosocial behavior.
How do young children learn to distinguish right from wrong? How do they acquire a sense of morality?
Moral reasoning, judgments of right and wrong, is influenced by children’s cognitive abilities and
develops in a predictable pattern (Skitka et al., 2016). Two-year-old children categorize behavior as good
or bad. They respond with distress when viewing or experiencing aggressive or potentially harmful
actions (Kochanska et al., 1995). By age 3, children judge a child who knocks another child off a swing
intentionally as worse than one who does so accidentally (Yuill & Perner, 1988). They begin to show an
understanding of and respect for basic normative standards, such as treating play partners fairly,
enforcing social norms, such as sharing, and feeling guilty when they violate them (Tomasello, 2018).
Four-year-old children can understand the difference between truth and lies (Bussey, 1992). By age 5,
children are aware of many moral rules, such as those regarding lying and stealing. They also
demonstrate conceptions of justice or fairness (e.g., “It’s my turn,” “Hers is bigger,” “It’s not fair!”). How
do these capacities develop?
Theories of Moral Reasoning and Behavior
There are many perspectives on moral development. Here we consider two classic views of moral
development: social learning theory and cognitive-developmental theory. Both consider a young child’s
moral values and behavior as first influenced by outside factors. But with development, moral values
become internalized and moral behavior becomes guided by inner standards.
Social Learning Theory
Social learning theory views all behavior, including moral behavior, as acquired through reinforcement
and modeling (Bandura, 1977; Grusec, 1992). Bandura and McDonald (1963) demonstrated that the
moral judgments of young children could be modified through a training procedure involving social
reinforcement and modeling. Parents and others naturally dole out reinforcement and punishment that
shape the child’s behavior. Modeling also plays a role in children’s moral development. Adults and other
children serve as models for the child, demonstrating appropriate (and sometimes not!) actions and
verbalizations. When children observe a model touching a forbidden toy, they are more likely to touch
the toy. Some research suggests that children who observe a model resisting temptation are less likely
to do so themselves (Rosenkoetter, 1973). However, models are more effective at encouraging rather
than inhibiting behavior that violates a rule or expectation. Children are more likely to follow a model’s
transgressions rather than his or her appropriate behavior.
Children are more likely to imitate models they view as competent and powerful (Bandura, 1977). They
are also more likely to imitate models that are perceived as warm and responsive rather than cold and
distant (Yarrow et al., 1973). Over the course of early childhood, children develop internalized standards
of conduct based on reinforcements, punishments, and observations of models (Bandura, 1986; Mussen
& Eisenberg-Berg, 1977). Those adopted standards and moral values are then internalized and used by
children as guides for behavior (Grusec & Goodnow, 1994). In this way, children’s behavior is shaped to
conform to the rules of society.
Cognitive-Developmental Theory
The cognitive-developmental perspective views moral development through a cognitive lens and
examines reasoning about moral issues: Is it OKto take a forbidden cookie from the cookie jar? To break
a rule? To not tell the truth? Similar to cognitive development, children are active in constructing their
own moral understanding about justice and fairness through social experiences with adults and peers
(Dahl, 2018, 2019; Killen et al., 2015).
Heteronomous Morality.
Cognitive-developmental theorist Jean Piaget (Piaget, 1932) studied how children understand rules. He
observed children playing marbles, a common schoolyard game in Piaget’s time, and asked them
questions about how to play the game. What are the rules? Where do the rules come from? Have the
rules for playing marbles always been the same? Can they be changed? Piaget found that preschool-age
children’s play was not guided by rules. The youngest children engaged in solitary play without regard
for rules, tossing and rolling the marbles about as they pleased. Piaget believed that moral thinking
develops in stages similar to those in his theory of cognition.
By 6 years of age, children enter the first stage of Piaget’s theory of morality, heteronomous morality
(also known as the morality of constraint). In this stage, as children first become aware of rules, they
view them as unalterable. The children interviewed by Piaget believed that people have always played
marbles in the same way and that the rules cannot be changed. At this stage, moral behavior is behavior
that is consistent with the rules set by authority figures. Young children see rules, even those created in
play, as absolute, behavior as either right or wrong; and they view the violation of rules as meriting
punishment regardless of intent (DeVries & Zan, 2003; Nobes & Pawson, 2003). Young children may
proclaim, without question, that there is only one way to play softball: As their coach advocates, the
youngest children must be first to bat. Preschoolers will hold to this rule, explaining that it is simply the
“right way” to play. It is not until middle childhood (Chapter 10) that children develop more flexible
views of fairness.
Preconventional Reasoning.
Kohlberg (1969, 1976) investigated moral development by posing hypothetical dilemmas about justice,
fairness, and rights that place obedience to authority and law in conflict with helping someone. Is
stealing ever permissible—even in order to help someone? Individuals’ responses change with
development; moral reasoning progresses through a universal order of stages representing qualitative
changes in conceptions of justice. Young children who display cognitive reasoning at the preoperational
stage are at the lowest level of Kohlberg’s scheme: preconventional reasoning. Kohlberg believed that
young children’s behavior is governed by self-interest, which is based on avoiding punishment and
gaining rewards. “Good” or moral behavior is a response to external pressure. Young children have not
internalized societal norms, and their behavior is motivated by desires rather than internalized principles.
Similar to Piaget’s ideas about cognitive and moral development, Kohlberg believed that children build
their own views of fairness and morality through social experiences with adults and peers (Smetana,
1995; Smetana & Braeges, 1990). The ability to take other people’s perspectives contributes to advances
in moral development. We will examine Kohlberg’s perspective in greater detail when we discuss middle
and late childhood (Chapter 10).
Children’s Conceptions of Moral, Social, and Personal Issues
Social experiences, such as disputes with siblings over toys, help young children develop conceptions
about justice and fairness (Dahl, 2018; Killen et al., 2015). As early as 3 years of age, children can
differentiate between moral issues, imperatives which concern people’s rights and welfare, and social
conventions or social customs (Smetana et al., 2018; Smetana & Braeges, 1990). They judge stealing an
apple, a moral violation, more harshly than violating a social convention, such as eating with one’s
fingers (Smetana et al., 2014).
Intent to harm, a moral violation, is also viewed harshly. In one study, 3- and 4½-year-old children
viewed an interchange in which one puppet struggled to achieve a goal, was helped by a second
puppet, and was violently hindered by a third puppet. When asked to distribute biscuits, the 4½-yearolds but not 3-year-olds were more likely to give more biscuits to the helper than the hinderer puppet.
Most explained the unequal distribution by referring to the helper’s prosocial behavior or the hinderer’s
antisocial behavior (Kenward & Dahl, 2011). Three-year-olds can succeed in generating intent-based
judgments when confronted with simplified tasks (Margoni & Surian, 2020).
In addition to moral and conventional issues, between ages 3 and 5, children come to differentiate
personal issues, matters of personal choice that do not violate rights, across home and school settings
(Turiel & Nucci, 2017). Individuals, including preschoolers, believe that they have control over matters of
personal choice, unlike moral issues whose violations are inherently wrong.
Cross-cultural research suggests that children in diverse cultures in Europe, Africa, Asia, Southeast Asia,
and North and South America differentiate moral, social conventional, and personal issues (Killen et al.,
2002; Turiel, 1998; Yau & Smetana, 2003). However, cultural differences in socialization contribute to
children’s conceptions. Although 3- through 7-year-old children from the United States and China
considered personal issues as permissible and up to the child, rather than the adults, their consideration
of moral transgressions varied (Yau & Smetana, 2003; Zhao & Kushnir, 2019). The Chinese children
tended to focus on the intrinsic consequences of the acts for others’ welfare and fairness, as compared
with the emphasis on avoiding punishment common in Western samples of preschoolers (Yau &
Smetana, 2003). These differences are consistent with cultural preferences for collectivism and
individualism. Whereas Western parents tend to emphasize individuality and independence, Chinese
parents tend to emphasize children’s obligations to the family and community (Chao, 1995; Yau &
Smetana, 2003). One study of 4-year-old Chinese children and their mothers showed that mothers
consistently drew children’s attention to transgressions, emphasizing the consequences for others. The
children learned quickly and were able to spontaneously discuss their mothers’ examples and strategies,
as well as reenact them in their own interactions, and their explanations reflected their own
understanding of rules and expectations in their own terms, rather than reflecting simple memorization
(Wang et al., 2008).
How adults discuss moral issues, such as truth-telling, harm, and property rights, influences how children
come to understand these issues. When adults, especially parents, discuss moral issues in ways that are
sensitive to the child’s developmental needs, children develop more sophisticated conceptions of
morality and advance in their moral reasoning (Janssens & Dekovic, 1997; Padilla-Walker & MemmottElison, 2020). As we have seen, there are cultural differences in how people think about moral and
conventional issues—and these conceptualizations are communicated, internalized, and transformed by
children as they construct their own concepts about morality.
Prosocial Behavior
As we have discussed earlier in this chapter, empathy and moral reasoning can motivate prosocial
behavior, behavior intended to help others. When does prosocial behavior emerge? A series of research
studies using the violation-of-expectation method (see Chapter 5) have suggested that infants as young
as 3 months may possess simple conceptions of prosocial behavior, such as preferring to look at
characters that help rather than hinder others (Van de Vondervoort & Hamlin, 2016). For toddlers as
young as 18 months, prosocial behavior is simple, such as the tendency to help adults, even unfamiliar
experimenters, by picking up markers that have fallen (Thompson & Newton, 2013). Between 18 and 24
months of age, toddlers show increasingly prosocial responses to others’ emotional and physical
distress, but their responses are limited to their own perspective. That is, they tend to offer the aid that
they themselves would prefer, such as bringing their own mother to help a distressed peer (Hepach et
al., 2012). Although toddlers are capable of prosocial responding to distressed others, spontaneous
prosocial behavior not prompted by adults is rare in toddlerhood (Eisenberg et al., 2015).
At 3½ years of age, children show more complex forms of instrumental assistance, or tangible help.
Compared to 18-month-old children, 3½-year-olds are more likely to help an adult by bringing a
needed object, to do so autonomously without the adult’s specific request, and to select an object
appropriate to the adult’s need (Svetlova et al., 2010). Young children may engage in prosocial behavior
for egocentric motives, such as the desire for praise and to avoid punishment and disapproval. With
development, children become less egocentric and more aware of others’ perspectives. In this way,
theory of mind contributes to prosocial behavior (Imuta et al., 2016). Young children’s prosocial behavior
becomes motivated by empathy and concern for others as well as internalized societal values for good
behavior (Eisenberg et al., 2013).
In addition to helping, children display prosocial behavior by sharing. Children’s views of sharing change
over time. Three-year-old children conceptualize fair sharing as strict equality, such as each child should
get the same amount of candy, no matter what (Damon, 1977; Enright et al., 1984). Using nonverbal
measures, researchers have shown that 3-year-old children identify and react negatively to unfair
distributions of stickers, especially if they receive fewer than another child (LoBue et al., 2011). Despite
endorsing norms of sharing, behavioral studies show that 3-year-old children tend to favor themselves
but become more likely to share with age (Smith et al., 2013). Sharing is also influenced by context. After
working together actively to obtain rewards in a collaboration task, most 3-year-old children share
equally with a peer (Warneken et al., 2011).
Between 3 and 5 years of age, young children show selectivity in sharing. Four- and 5-year-olds believe
in an obligation to share, but they often allocate rewards based on observable characteristics, such as
age, size, or other obvious physical characteristics (e.g., “The oldest should get more candy”). Often
these decisions are based on personal desires and characteristics that adults would deem irrelevant, such
as, “Girls should get more because they’re girls!” When told that they must make an unequal
distribution, 5-year-olds tend to share more with others whom they expect will reciprocate and more
with friends than with peers they dislike (Paulus & Moore, 2014). They are also more likely to share with
friends and persons known to them than strangers.
Like adults, young children’s judgments about whether to help are influenced by considerations such as
people’s welfare and needs as well as the situation (Dahl & Paulus, 2019). They are more likely to help
when there is little cost to themself but are less likely to help as the costs of helping someone else rises.
Young children share more with children and adults who show prosocial behaviors such as sharing and
helping others and they view helping as less acceptable if the recipient is trying to steal (Dahl &
Brownell, 2019; Kuhlmeier et al., 2014). Notably, young children’s perspective on sharing shifts from an
emphasis on equality to equity and they begin to consider others’ wealth and distribute more resources
to poor others than rich others (Paulus et al., 2018). Children who have more contact with children of
lesser wealth are more likely to allocate resources based on wealth, allocating more to a low-wealth peer
than a high-wealth peer (Elenbaas, 2019).
One example of prosocial behavior is sharing. Sharing becomes more
equitable and complex with development.
iStock/FatCamera
Early childhood prosocial behavior is associated with positive peer relationships, mental health, and
social competence in preschool and beyond (Malti & Dys, 2018). Prosocial children tend to show low
levels of aggressive and problem behaviors. They tend to be successful in school and score high on
measures of vocabulary, reading, and language—perhaps because prosocial children are friendly and
engage in interaction with teachers and peers (Eisenberg et al., 2015; Miller & Hastings, 2020).
Influences on Prosocial Behavior
Prosocial behavior is influenced by many interacting factors, including biology and genes, family
contexts, the larger social context, and the development of reasoning skills. Let’s explore each of these
influences.
Biological Influences.
Genetic factors are thought to contribute to individual differences in prosocial behavior (Waldman et al.,
2011). Twin studies have revealed that adult identical twins show more similar reports of prosocial
behavior than do their fraternal twin peers (Knafo-Noam et al., 2015). Several genes have been
implicated in prosocial tendencies, including one that influences the hormone oxytocin, which is
associated with attachment and other socioemotional behaviors (Carter, 2014). A child’s inborn
temperament influences how the child regulates emotion, which is related to feelings of empathy for a
distressed child or adult and, in turn, whether empathetic feelings result in personal distress or prosocial
behavior (Eisenberg et al., 2015). Children who are unable to successfully regulate their emotions tend to
react to distressed others with heightened physiological arousal, including increases in heart rate and
brain activity in regions known to process negative emotions, suggesting a feeling of being
overwhelmed that can interfere with prosocial responding (Miller, 2018).
Twins tend to show similar patterns of sharing.
iStock/Alex Liew
Emotional Influences.
Empathy and concern for others emerge in toddlerhood and often prompt prosocial behavior. Selfconscious emotions, such as guilt and pride, influence prosocial behavior. In response to guilt, 2- and 3year-olds are motivated to repair damage that they have caused (Vaish, 2018). Guilt also motivates
children to behave prosocially as well as repair prosocial interactions with others, such as by apologizing
(Vaish & Hepach, 2020). When 3- and 4-year-old children feel pride in response to an achievement, they
are more likely to offer spontaneous help to a person in need (Ross, 2017). Self-conscious emotions and
the self-evaluations inherent in them might motivate prosocial behavior in an attempt to maintain an
ideal self. At about 3–5 years of age children begin to anticipate guilt in response to wrongdoing, which
predicts prosocial behavior such as sharing (Malti & Dys, 2018).
Family Influences.
Prosocial behaviors, such as sharing, comforting, and helping, emerge through everyday interactions
with caregivers from birth (Dahl & Brownell, 2019). Rich interactions with parents engage the emotions,
cognitions, and behaviors critical to prosocial responding (Brownell, 2016). The secure attachment that
accompanies warm, sensitive parenting aids in the development of emotional regulation, a predictor of
empathy and prosocial responding (Beier et al., 2019; Spinrad & Gal, 2018). Parents of prosocial children
draw attention to models of prosocial behavior in peers and in media, such as in storybooks, movies,
and television programs. As suggested earlier, parents may also describe feelings and model
sympathetic concern and the use of language to discuss feelings. Young children whose parents do
these things are more likely to use words to describe their thoughts and emotions and attempt to
understand others’ emotional states (Taylor et al., 2013).
Parents also actively encourage prosocial behavior by including young children in their household and
caregiving activities (Dahl, 2015). Parents’ encouragement of children’s participation in household
cleanup routines predicts children’s willingness to help another adult in a new context (Hammond &
Carpendale, 2015). Children’s prosocial behavior emerges out of prosocial activity shared with adults,
and parental encouragement promotes its development (Brownell, 2016).
At the same time as parents influence children, children play a role in their own development by
influencing their parents (Miller & Hastings, 2020). One study that followed children from 4½ years of
age through sixth grade found that maternal sensitivity influenced children’s prosocial behavior and that
prosocial behavior, in turn, predicted mothers’ subsequent sensitivity, suggesting that mothers and
children influence each other (Newton et al., 2014). Children who are kind, compassionate, and helpful
elicit responsive and warm parenting from their mothers.
Siblings offer opportunities to learn and practice helping and other prosocial behavior (Hughes et al.,
2018). Older siblings who display positive emotional responsiveness promote preschoolers’ emotional
and social competence. Researchers have observed that children with siblings tend to develop a theory
of mind earlier than those without siblings (Kramer, 2014). As we have seen, the perspective-taking and
cognitive skills that comprise theory of mind promote emotional understanding and prosocial behavior.
Contextual Influences.
The broader social world also influences the development of prosocial behavior. Collectivist cultures, in
which people live with extended families, work is shared, and the maintenance of positive relationships
with others is emphasized, tend to promote prosocial values and behavior more so than do cultures that
emphasize the individual, as is common in most Western cultures (Eisenberg et al., 2015). One study of
mother–child dyads in Japan and the United States found that the Japanese mothers of 4-year-old
children tended to emphasize mutuality in their interactions, stressing the relationship (e.g., “This puzzle
is difficult for us. Let’s see if we can solve it.”). In contrast, the U.S. mothers tended to emphasize
individuality (e.g., “This puzzle is hard for you, isn’t it? Let’s see you try again.”) (Dennis et al., 2002).
These different styles influence how children display empathy, whether as sharing another’s emotion or
simply understanding another’s emotion.
These cultural differences extend to children’s reasons for sharing. When Filipino and American fifthgraders were presented with hypothetical scenarios that required them to determine how resources
should be shared, both the Filipino and American children preferred equal division of the resources
regardless of merit or need (Carson & Banuazizi, 2008). However, the children offered different
explanations of their choices. U.S. children emphasized that the characters in the scenario performed
equally and therefore deserved equal amounts of the resources, reflecting U.S. culture’s emphasis on
individuality and merit. Filipino children, on the other hand, tended to be more concerned with the
interpersonal and emotional consequences of an unequal distribution, in line with their culture’s
emphasis on the collective and the importance of interpersonal relationships (Carson & Banuazizi, 2008).
Aggressive Behavior
Although their capacities for empathy and prosocial responses increase, young children commonly show
aggressive behavior, behavior that harms or violates the rights of others. Most infants and children
engage in some physically aggressive behaviors—hitting, biting, or kicking—some of the time (Tremblay
et al., 2004). Some aggression is normal and not an indicator of poor adjustment.
The most common form of aggression seen in infancy and early childhood is instrumental aggression,
aggression used to achieve a goal, such as obtaining a toy. Instrumental aggression is often displayed as
physical aggression (Hay et al., 2011). A child who grabs a crayon out of another child’s hand is often
motivated to obtain the crayon, not to hurt the other child. In addition to fighting over toys, preschool
children often battle over space (“I was sitting there!”). Instrumental aggression increases from
toddlerhood into early childhood, around age 4, as children begin to play with other children and act in
their own interests. Indeed, instrumental aggression usually occurs during play. It is often displayed by
sociable and confident preschoolers, suggesting that it is a normal aspect of development.
In the preschool years, children may engage in instrumental aggression when
they want to obtain an object, such as the toy in this picture.
iStock/Zabavna
By ages 4 to 5, most children develop the self-control to resist aggressive impulses and the language
skills to express their needs. Now, physical aggression declines and verbal aggression becomes more
frequent (Eisner & Malti, 2015). Verbal aggression is a form of relational aggression, intended to harm
others’ social relationships (Ostrov & Godleski, 2010). In preschool and elementary school, relational
aggression often takes the form of name-calling and excluding peers from play (Pellegrini & Roseth,
2006).
Most children learn to inhibit aggressive impulses, but a small minority of children show high levels of
aggression (e.g., repeated hitting, kicking, biting) that increase during childhood (Tremblay, 2014). Young
children who show high levels of aggression are more likely to have experienced coercive parenting,
family dysfunction, and low income; they are also more likely to have mothers with a history of antisocial
behavior and early childbearing (Wang et al., 2013). Children who do not develop the impulse control
and self-management skills to inhibit their aggressive responses may continue and escalate aggressive
behavior over the childhood years and show poor social and academic outcomes during the school-age
years and beyond (Gower et al., 2014).
Thinking in Context: Lifespan Development
Compare the social learning and cognitive-developmental perspectives on moral development.
1. What are the strengths and weaknesses of each?
2. In your view, is moral development better explained by modeling and reinforcement or by changes
in thinking? Explain.
3. Aggression is inborn and prosocial behavior is learned. Agree or disagree? Explain.
Thinking in Context: Intersectionality
Early conceptions of justice emerge as young children become able to distinguish among moral, social
conventional, and personal issues.
1. How do children’s contexts influence their conceptions of morality and fairness?
2. In addition to cross-cultural differences, might we expect intersectional influences on young
children’s beliefs about justice? Explain.
3. Consider parents’ experiences with and observations of injustice, including racism, unjust arrests,
unemployment, discrimination, and violence. To what degree do you think young children are aware
of injustice?
4. How might young children’s immersion in contexts of injustice influence their thinking about
morality, social convention, and personal issues?
5. Given what you know about cognition and moral development, how can parents discuss social
justice in ways that young children can grasp?
FAMILIES IN EARLY CHILDHOOD
LEARNING OBJECTIVE
8.4 Compare styles of parenting and discipline and their associations with child outcomes.
The home context and family relationships, especially the parent–child relationship, play a large role in
shaping children’s social and emotional development.
Parenting Styles
Parenting style is the emotional climate of the parent–child relationship—the degree of warmth,
support, and boundaries that parents provide. Parenting style influences parents’ efficacy, their
relationship with their children, and their children’s development. Parenting styles are displayed as
enduring sets of parenting behaviors that occur across situations to form childrearing climates. These
behaviors combine warmth and acceptance with limits and rule-setting in various degrees. In a classic
series of studies, Diana Baumrind (1971, 2013) examined 103 preschoolers and their families through
interviews, home observations, and other measures. She identified several parenting styles and their
effects on children (see Table 8.1).
Table 8.1 Parenting Styles
Parenting
Style
Authoritative
Authoritarian
Warmth Control
Permissive
Indifferent
High
Low
High
Low
Firm, consistent, coupled with discussion
High, emphasizing control and punishment without discussion or
explanation
Low
Low
Parenting style is an important influence on development. Authoritarian
parenting emphasizes rigid strictness over warmth. Uninvolved parenting can
make children feel invisible. Extreme forms of uninvolved parenting
constitute neglect.
Jamie Grill/Getty Images; iStock/LightFieldStudios
Authoritarian Parenting Style
In Baumrind’s classification, parents who use an authoritarian parenting style emphasize behavioral
control and obedience over warmth. Children are to conform to parental rules without question, simply
“because I say so.” Violations are often accompanied by forceful punishment, such as yelling,
threatening, or spanking. Parents with an authoritarian style are less supportive and warm and more
detached, perhaps even appearing cold.
Children raised by authoritarian parents tend to be withdrawn, mistrustful, anxious, and angry (Rose et
al., 2018). They tend to interact with peers in disruptive ways and react with hostility in response to
frustrating peer interactions (Gagnon et al., 2013). Children reared in harsh, controlling parenting
environments show more behavioral problems and display less prosocial behavior than other children,
from early childhood into adolescence (Baumrind et al., 2010; Pinquart, 2017; Wong et al., 2020).
Moreover, parents and children influence each other. As parenting becomes more harsh, children tend to
display more behavior problems, which tends to increase negative interactions with parents.
Permissive Parenting Style
Parents who adopt a permissive parenting style are warm and accepting, even indulgent. They
emphasize self-expression and have few rules and behavioral expectations for their children. When rules
are set, they often are not enforced or are enforced inconsistently. Parents with a permissive parenting
style often allow children to monitor their own behavior. Autonomy is not granted gradually and in
developmentally appropriate ways. Instead, children are permitted to make their own decisions, such as
deciding their bedtime or monitoring their screen time, at any early age, often before they are able.
Many children lack the self-regulation capacities to appropriately limit their activity. Compared with their
peers, preschoolers raised with a permissive parenting style tend to be more socioemotionally immature
than their peers, more rebellious, impulsive, and bossy, and show less self-control, self-regulatory
capacity, and persistence (Hoeve et al., 2011; Piotrowski et al., 2013). A permissive parenting style also
places children at risk for poor school achievement and more behavior problems, posing long-term risks
for development (Jewell et al., 2008).
Uninvolved Parenting Style
Parents with an uninvolved parenting style focus on their own needs rather than those of their children.
Parents who are under stress, emotionally detached, or depressed often lack time or energy to devote to
their children, putting them at risk for an uninvolved parenting style (Baumrind, 2012). Uninvolved
parents provide little support or warmth, exert little control, and fail to recognize their children’s need
for affection and direction. As a result, young children reared in neglectful homes show less knowledge
about emotions than do children raised with other parenting styles (Sullivan et al., 2010). At the extreme,
uninvolved parenting is neglectful and a form of child maltreatment. Uninvolved parenting can have
negative consequences for all forms of children’s development—cognitive, emotional, social, and even
physical.
Authoritative Parenting Style
The most positive developmental outcomes are associated with what Baumrind termed the authoritative
parenting style. Authoritative parents are warm and sensitive to children’s needs but also are firm in
their expectations that children conform to appropriate standards of behavior. While exerting firm,
reasonable control, they engage their children in discussions about standards and grant them
developmentally appropriate levels of autonomy, permitting decision making that is appropriate to the
children’s abilities (Baumrind, 2013). When a rule is violated, authoritative parents explain what the
children did wrong and impose limited, developmentally appropriate punishments that are closely
connected to the misdeed. Authoritative parents value and foster children’s individuality. They
encourage their children to have their own interests, opinions, and decisions, but ultimately, they control
the children’s behavior.
Children of authoritative parents display confidence, self-esteem, and curiosity, and score higher on
measures of social skills, prosocial behavior, executive function, and academic achievement; these
positive effects persist throughout childhood into adolescence (Helm et al., 2020; Pinquart & Gerke,
2019; Sosic-Vasic et al., 2017; Wong et al., 2020). Parents in a given household often share a common
parenting style, but when they do not, the presence of authoritative parenting in at least one parent
buffers the negative outcomes associated with the other style and predicts positive adjustment (Hoeve
et al., 2011; McKinney & Renk, 2011).
Discipline
Discipline refers to the methods a parent uses to teach and socialize children toward acceptable
behavior. Learning theory can account for the effect of parents’ discipline strategies on children’s
behavior. Specifically, the consequences of a child’s behavior, whether it is reinforced or punished,
influence the child’s future behavior. Effective reinforcement must be viewed as rewarding to the child
and can be tangible, such as money or candy, or intangible, such as attention or a smile. To change a
child’s behavior, reinforcement must be administered consistently when the desired behavior occurs.
Eventually the reinforcement becomes internalized by the child and the behavior itself becomes
reinforcing, associated with pleasurable feelings and, eventually, a positive feeling of accomplishment.
Physical Punishment
Physical punishment, also known as corporal punishment or spanking, is against the law in over 50
countries (Grogan-Kaylor et al., 2018), yet hotly contested in other countries. Parents in many countries
within Asia, Africa, the Middle East, and North and South America report that spanking is acceptable,
appropriate, and sometimes necessary (Hicks-Pass, 2009; Oveisi et al., 2010). In the United States, the
majority of adults report that they were spanked as children without harm, and 80% of a sample of U.S.
parents report spanking their young children (Gershoff et al., 2018). Why the controversy on spanking if
it occurs in most cultures?
Research suggests that physical punishment tends to increase compliance only temporarily. Longitudinal
research suggests that physical punishment is associated with behavior problems in infancy,
toddlerhood, and early childhood through age 5 (Choe et al., 2013; Lee et al., 2013; Mendez, Durtschi,
Neppl, & Stith, 2016). Physical punishment is also damaging to the parent–child relationship (Balan et al.,
2017; Coley et al., 2014; Gershoff & Grogan-Kaylor, 2016; Sege & Siegel, 2018). In one recent study, the
use of corporal punishment at age 3 was associated with declines in the quality of parent–child
interaction at 5 years of age, suggesting that physical punishment may erode the parent–child
relationship (Laible et al., 2020). When a parent loses self-control and yells, screams, or hits a child, the
child may feel helpless, become fearful of the parent, avoid him or her, and become passive.
Parental use of spanking is associated with internalizing problems (such as anxiety and depression),
externalizing problems (such as aggression), impaired cognitive ability, low self-esteem in childhood and
adolescence, and mental health problems and antisocial behavior in adulthood. Physical punishment can
foster the very behavior that parents seek to stop. Parents often punish children for aggressive behavior,
yet physical punishment models the use of aggression as an effective way of resolving conflict and other
problems, teaching children that might makes right (D’Souza et al., 2016; Sege & Siegel, 2018). Parents
who reported using physical discipline were nearly three times as likely to report aggressive behaviors
like hitting and kicking in their young children than parents who did not use physical discipline
(Thompson et al., 2017). One recent analysis concluded that the effects of physical punishment are
similar to those of child maltreatment and that parents should avoid physical punishment and health
professionals and policymakers should advocate against it and devise means of educating parents about
its negative effects (Gershoff et al., 2018).
What can parents do about their children’s undesirable behavior? While physical punishment is not
advised, noncorporal punishment can be effective, in small doses and within specific contexts. Running
into the street or touching a hot stove are behaviors that are dangerous to children or to others. These
behaviors must be stopped immediately to prevent injury. To be effective, punishment should occur
immediately after the dangerous behavior, be applied calmly and consistently, be clearly connected to
the behavior, and be explained to the child. The purpose of such punishment is to keep the child from
engaging in dangerous behavior, to make the child comply, but not to feel guilt.
Time out removes the child from overstimulating situations and stops
inappropriate behaviors without humiliating him or her. Time out is effective
when it is accompanied by an explanation and a warm parent–child
relationship.
iStock/sdgamez
Time out from reinforcement, commonly referred to as time out, entails removing a child from the
situation and its rewarding stimuli, including social contact, for a short period of time (Dadds & Tully,
2019). Implemented correctly, time out is effective in reducing inappropriate behavior (Lawrence et al.,
2021; Morawska & Sanders, 2011). Effective punishment is administered calmly, privately, and within the
context of a warm parent–child relationship, and it is accompanied by an explanation so that the child
understands the reason for the punishment (Baumrind, 2013). It should be noted that even experts
debate the effects of mild “nonabusive” spanking; some argue that it may be effective as a “backup
method” when young children fail to cooperate with milder tactics, such as time out (Larzelere et al.,
2019). Despite estimates that the vast majority of parents spank their children, recent evidence with a
sample of over 16,000 parents suggests that the use of spanking has declined dramatically over the past
25 years (Mehus and Patrick, 2021) (Figure 8.1). These findings are encouraging, but pediatricians and
developmental scientists agree that parents can benefit from education about alternatives discipline
strategies.
Description
Figure 8.1 Trend in the Prevalence of Spanking
Source: Adapted from Mehus & Patrick (2021).
Inductive Discipline
Inductive discipline, methods that use reasoning, are effective alternatives to spanking in changing a
child’s behavior (AAP Committee on Psychosocial Aspects of Child and Family Health, 1998; Lawren